UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 14A

Proxy Statement Pursuant to Section 14(a) of the

Securities Exchange Act of 1934

Filed by the Registrant  ☒                             Filed by a Party other than the Registrant  ☐

Check the appropriate box:

QEP RESOURCES, INC.

(Name of Registrant as Specified in its Charter)

(Name of Person(s) Filing Proxy Statement, if other than the Registrant)

Payment of Filing Fee (Check the appropriate box):

LETTER TO STOCKHOLDERS OF QEP RESOURCES, INC.

Dear Stockholders of QEP Resources, Inc.:

On December 20, 2020, QEP Resources, Inc. (“QEP”), Diamondback Energy, Inc. (“Diamondback”) and Bohemia Merger Sub, Inc., a direct, wholly owned subsidiary of Diamondback (“Merger Sub”), entered into an Agreement and Plan of Merger (as it may be amended from time to time, the “merger agreement”), under which, upon the terms and subject to the conditions set forth therein, Merger Sub will be merged with and into QEP (the “merger”), with QEP surviving as a direct, wholly owned subsidiary of Diamondback. If the merger is completed, QEP stockholders will receive, in exchange for each share of common stock, par value $0.01 per share, of QEP (“QEP common stock”) held immediately prior to the merger, 0.050 of a share of common stock, par value $0.01 per share, of Diamondback (“Diamondback common stock”). The board of directors of QEP (the “QEP board”) has unanimously approved the merger agreement and recommends that QEP stockholders vote in favor of adopting the merger agreement.

Based on Diamondback’s closing stock price on February 5, 2021, the most recent practicable date for which such information was available, the merger consideration represented approximately $3.22 in value per share of QEP common stock, which represents a premium of approximately 39.4% over QEP’s closing stock price on December 18, 2020, the last trading day before the public announcement of the execution of the merger agreement with Diamondback. The value of the merger consideration to be received in exchange for each share of Diamondback common stock will fluctuate with the market value of Diamondback common stock until the transaction is complete. Diamondback common stock is quoted on the Nasdaq Global Select Market under the symbol “FANG,” and QEP common stock is quoted on the New York Stock Exchange under the symbol “QEP.” Following the completion of the merger, it is anticipated that persons who were stockholders of Diamondback and QEP immediately prior to the merger will own approximately 93% and 7% of the combined company following the merger, respectively.

The merger cannot be completed without approval of the proposal to adopt the merger agreement by the affirmative vote of holders of a majority of the outstanding shares of QEP common stock entitled to vote thereon. Because of this, QEP is holding a special meeting of its stockholders on March 16, 2021 to vote on the proposal necessary to complete the merger. At the special meeting, QEP stockholders will also be asked to approve the non-binding compensation advisory proposal and the adjournment proposal, both of which are not a condition to the consummation of the merger. Information about the special meeting, the merger, the merger agreement, and the other business to be considered by stockholders at the special meeting is contained in this proxy statement/prospectus. The QEP board has fixed the close of business on February 5, 2021 as the record date for the determination of QEP stockholders entitled to notice of, and to vote at, the special meeting. Any stockholder entitled to attend and vote at the special meeting is entitled to appoint a proxy to attend and vote on such stockholder’s behalf. Such proxy need not be a holder of QEP common stock. We urge you to read this proxy statement/prospectus and the annexes and documents incorporated by reference carefully. You should also carefully consider the risks that are described in the “Risk Factors” section beginning on page 35.

The QEP board has unanimously determined that the merger agreement and the transactions contemplated thereby, including the merger, are fair to, and in the best interests of, the QEP stockholders, approved and declared advisable the merger agreement and the transactions contemplated thereby, including the merger, and directed that the merger agreement be submitted to QEP stockholders for adoption at a meeting of such stockholders, and unanimously recommends that QEP stockholders vote “FOR” the proposal to adopt the merger agreement and the transactions contemplated thereby, including the merger.

Your vote is very important regardless of the number of shares of QEP common stock that you own.

Whether or not you plan to attend the special meeting, please submit your proxy as soon as possible by following the instructions on the accompanying proxy card to make sure that your shares are represented at the meeting. If your shares are held in the name of a broker, bank or other nominee, please follow the instructions on the voting instruction form furnished by the broker, bank or other nominee. You must provide voting instructions by filling out the voting instruction form in order for your shares to be voted.

In light of public health concerns regarding the ongoing COVID-19 pandemic and in consideration of medical and governmental recommendations and orders limiting the number of persons that may gather at public events, the special meeting will be held in a virtual meeting format only. You will not be able to attend the special meeting physically in person. Thank you for your continued support, interest and investment in QEP.

Sincerely,

Timothy J. Cutt President & Chief Executive Officer QEP Resources, Inc.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of the securities to be issued under the accompanying proxy statement/prospectus or passed upon the adequacy or accuracy of the disclosure in this document. Any representation to the contrary is a criminal offense.

The proxy statement/prospectus is dated February 10, 2021 and is first being mailed to stockholders of QEP on or about February 10, 2021.

NOTICE OF THE SPECIAL MEETING OF STOCKHOLDERS

TO BE HELD VIRTUALLY VIA THE INTERNET ON MARCH 16 , 2021

To the Stockholders of QEP Resources, Inc.:

On behalf of QEP Resources, Inc. (“QEP”) and the Board of Directors of QEP (the “QEP board”), I am pleased to invite you to a special meeting of stockholders of QEP (the “QEP special meeting”), which will be held virtually via the Internet on March 16, 2021, at 8:00 a.m., Mountain Time, to consider and vote on the following proposals:

In light of public health concerns regarding the ongoing COVID-19 pandemic, the QEP special meeting will be held in a virtual meeting format only, via live webcast, and there will not be a physical meeting location. You will be able to attend the QEP special meeting online and vote your shares electronically at the meeting by visiting www.virtualshareholdermeeting.com/QEP2021SM (the “QEP special meeting website”).

QEP stockholder approval of the merger proposal is required to complete the merger between Merger Sub and QEP, as contemplated by the merger agreement. QEP stockholders will also be asked to approve the non-binding compensation advisory proposal and the adjournment proposal, both of which are not conditions to the consummation of the merger. QEP does not intend to transact any other business at the QEP special meeting or any adjournment or postponement thereof. The record date for the QEP special meeting has been set as February 5, 2021. Only QEP stockholders of record as of the close of business on such record date are entitled to notice of, and to vote at, the QEP special meeting or any adjournments and postponements of the QEP special meeting. For additional information regarding the QEP special meeting, see the section entitled “Special Meeting of QEP Stockholders” beginning on page 52 of the proxy statement/prospectus accompanying this notice.

The QEP board unanimously recommends that holders of QEP common stock vote “FOR” the merger proposal and “FOR” the non-binding compensation advisory proposal and “FOR” the adjournment proposal.

The QEP stockholder proposals are described in more detail in the accompanying proxy statement/prospectus, which you should read carefully and in its entirety before you vote. A copy of the merger agreement is attached as Annex A to the accompanying proxy statement/prospectus.

PLEASE VOTE AS PROMPTLY AS POSSIBLE, WHETHER OR NOT YOU PLAN TO ATTEND THE QEP SPECIAL MEETING VIA THE QEP SPECIAL MEETING WEBSITE. IF YOU LATER DESIRE TO REVOKE OR CHANGE YOUR PROXY FOR ANY REASON, YOU MAY DO SO IN THE MANNER DESCRIBED IN THE ACCOMPANYING PROXY STATEMENT/PROSPECTUS. FOR FURTHER INFORMATION CONCERNING THE PROPOSALS BEING VOTED UPON, USE OF THE PROXY AND OTHER RELATED MATTERS, YOU ARE URGED TO READ THE ACCOMPANYING PROXY STATEMENT/PROSPECTUS.

QEP Resources, Inc.

Mary Shafer-Malicki, Chair of the Board

Denver, Colorado

February 10, 2021

REFERENCES TO ADDITIONAL INFORMATION

This proxy statement/prospectus incorporates by reference important business and financial information about Diamondback Energy, Inc. (“Diamondback”) and QEP Resources, Inc. (“QEP”) from other documents that are not included in or delivered with this proxy statement/prospectus, including documents that Diamondback and QEP have filed with the U.S. Securities and Exchange Commission (the “SEC”). For a listing of documents incorporated by reference herein, see the sections entitled “Where You Can Find More Information” and “Information Incorporated by Reference” on page 180.

You may request copies of this proxy statement/prospectus and any of the documents incorporated by reference herein or other information concerning Diamondback or QEP, without charge, upon written or oral request to the applicable company’s principal executive offices. The respective addresses and phone numbers of such principal offices are listed below.

To obtain timely delivery of these documents before the special meeting of stockholders of QEP (the “QEP special meeting”), QEP stockholders must request the information no later than March 9, 2021, which is five business days before the date of the QEP special meeting.

You may also obtain any of the documents incorporated by reference into this proxy statement/prospectus free of charge through the SEC’s website at www.sec.gov. In addition, you may obtain copies of many of these documents, free of charge, from Diamondback by accessing Diamondback’s website at http://www.diamondbackenergy.com under the “Investors” link and then under the heading “Financial Reports” or from QEP by accessing QEP’s website at http://www.qepres.com under the “Investors” link and then under the heading “Financial Information” and “SEC Filings.”

In addition, if you have questions about the merger or this proxy statement/prospectus, would like additional copies of this proxy statement/prospectus or need to obtain proxy cards or other information related to the proxy solicitation, contact Georgeson LLC, the proxy solicitor for QEP, toll-free at (800) 903-2897. You will not be charged for any of these documents that you request.

ABOUT THIS PROXY STATEMENT/PROSPECTUS

This document, which forms part of a registration statement on Form S-4 filed with the SEC by Diamondback (File No. 333-252338 ), constitutes a prospectus of Diamondback under Section 5 of the Securities Act of 1933, as amended (the “Securities Act”) with respect to the shares of common stock of Diamondback, par value $0.01 per share (“Diamondback common stock”), to be issued to the holders (the “QEP stockholders”) of shares of common stock, par value $0.01 per share, of QEP (“QEP common stock”) pursuant to the Agreement and Plan of Merger, dated December 20, 2020 (as amended from time to time, the “merger agreement”), by and among Diamondback, Bohemia Merger Sub Inc. (“Merger Sub”) and QEP.

This document also constitutes a notice of meeting and proxy statement of QEP under Section 14(a) of the Securities Exchange Act of 1934, as amended (the “Exchange Act”).

Diamondback has supplied all information contained or incorporated by reference herein relating to Diamondback, and QEP has supplied all information contained or incorporated by reference herein relating to QEP. Diamondback and QEP have both contributed to the information relating to the merger and the merger agreement contained in this proxy statement/prospectus.

You should rely only on the information contained in or incorporated by reference herein in connection with any vote, the giving or withholding of any proxy or any investment decision in connection with the merger agreement. Diamondback and QEP have not authorized anyone to provide you with information that is different from that contained in or incorporated by reference herein. This proxy statement/prospectus is dated February 10, 2021, and you should not assume that the information contained in this proxy statement/prospectus is accurate as of any date other than such date unless otherwise specifically provided herein. Further, you should not assume that the information incorporated by reference herein is accurate as of any date other than the date of the incorporated document. Neither the mailing of this proxy statement/prospectus to stockholders of QEP, nor the issuance by Diamondback of shares of Diamondback common stock pursuant to the merger agreement, will create any implication to the contrary.

All currency amounts referenced in this proxy statement/prospectus are in U.S. dollars.

TABLE OF CONTENTS

QUESTIONS AND ANSWERS ABOUT THE MERGER AND THE QEP SPECIAL MEETING

The following are answers to certain questions that you may have regarding the QEP special meeting. This section may not provide all the information that might be important to you in determining how to vote. Additional important information is also contained in the annexes to, and the documents incorporated by reference in, this document.

The merger agreement must be adopted by the QEP stockholders in accordance with the General Corporation Law of the State of Delaware (the “DGCL”) and its charter and bylaws (the “QEP organizational documents”) in order for the merger to be consummated. QEP is holding a special meeting of its stockholders (the “QEP special meeting”) to obtain that approval. QEP stockholders will also be asked to vote on a non-binding advisory proposal to approve certain compensation that may be paid or become payable to QEP’s named executive officers that is based on or otherwise relates to the merger. Your vote is very important. We encourage you to submit a proxy to have your shares of QEP common stock voted as soon as possible.

In light of the public health concerns regarding the ongoing COVID-19 pandemic, the QEP special meeting will be held in a virtual meeting format only, via live webcast, and there will not be a physical meeting location. You will be able to attend the QEP special meeting online and vote your shares electronically at the meeting by visiting www.virtualshareholdermeeting.com/QEP2021SM (the “QEP special meeting website”). To attend the meeting on the QEP special meeting website, please follow the instructions provided on the enclosed proxy card and the QEP special meeting website.

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Under the current New York Stock Exchange (the “NYSE”) rules, brokers, banks or other nominees do not have discretionary authority to vote on any of the proposals at the QEP special meeting. Because the only proposals for consideration at the QEP special meeting are nondiscretionary proposals, it is not expected that there will be any broker non-votes at the QEP special meeting. However, if there are any broker non-votes, they will have (i) the same effect as a vote “AGAINST” the merger proposal, (ii) no effect on the non-binding compensation advisory proposal and (iii) no effect on the adjournment proposal.

The non-binding compensation advisory proposal. Approval of the non-binding compensation advisory proposal requires the affirmative vote of a majority of the shares of QEP common stock present in person or represented by proxy at the QEP special meeting and entitled to vote on the proposal. Abstentions will have the same effect as a vote “AGAINST” the proposal, and broker non-votes will have no effect on the outcome of the vote. As an advisory vote, this proposal is not binding upon QEP, the QEP board, Diamondback or the board of directors of Diamondback (the “Diamondback board” or the “Diamondback board of directors”), and approval of this proposal is not a condition to completion of the merger.

The adjournment proposal. Approval of the adjournment proposal requires the affirmative vote of a majority of the shares of QEP common stock present in person or represented by proxy at the QEP special meeting and entitled to vote on the proposal. If QEP stockholders approve the adjournment proposal, subject to the terms of the merger agreement, QEP could adjourn the QEP special meeting and use the additional time to solicit additional proxies, including soliciting proxies from QEP stockholders who have previously voted. QEP does not intend to call a vote on the adjournment proposal if the merger proposal is approved at the QEP special meeting.

Virtual attendance at the QEP special meeting constitutes present in person for purposes of the quorum requirement under the Amended and Restated Bylaws of QEP (“QEP’s bylaws”).

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QEP stockholders will not be entitled to receive any fractional shares of Diamondback common stock in the merger, and no QEP stockholders will be entitled to receive dividends, voting rights or any other rights in respect of any fractional shares of Diamondback common stock. Each holder of shares of QEP common stock exchanged pursuant to the merger who would otherwise have been entitled to receive a fraction of a share of Diamondback common stock (after taking into account all certificates and book-entry shares delivered by such holder) will receive, in lieu thereof, cash (without interest) in an amount equal to the product of (i) such fractional part of a share of Diamondback common stock multiplied by (ii) the volume weighted average price of Diamondback common stock for the five consecutive trading days ending on the date that is two trading days prior to the closing date as reported by Bloomberg, L.P. For additional information regarding the merger consideration, see the sections entitled “The Merger—Consideration to QEP Stockholders” and “The Merger Agreement—Effect of the Merger on Capital Stock; Merger Consideration” beginning on pages 60 and 112, respectively.

At the effective time of the merger, each unvested award of restricted shares of QEP common stock that is outstanding immediately prior to the effective time of the merger will be converted into a number of time-based restricted shares of Diamondback common stock (rounded to the nearest whole share) equal to the product of (i) the total number of shares of QEP common stock subject to such award immediately prior to the effective time of the merger multiplied by (ii) the exchange ratio. Following the effective time, the restricted shares will be subject to the same terms and conditions (including time-based and termination related vesting conditions) that were applicable to such restricted shares under the applicable QEP stock plan and award agreement immediately prior to the effective time of the merger.

QEP PSU Awards

At the effective time of the merger, each unvested award of performance share units denominated in shares of QEP common stock that is outstanding immediately prior to the effective time of the merger will be converted into time-based restricted stock units in respect of that number of shares of Diamondback common stock (rounded to the nearest whole share) equal to the product of (i) the number of shares of QEP common stock subject to such award immediately prior to the effective time of the merger that would have been earned under the applicable terms of such award based upon the higher of (A) 100% of the target level of performance and (B) actual performance through the closing date (as determined by QEP’s compensation committee) multiplied by (ii) the exchange ratio. The performance share unit awards will be converted on the same terms and conditions (including time-based and termination related vesting conditions) applicable to such awards under the applicable QEP stock plan and award agreement immediately prior to the effective time of the merger (other than any performance-based vesting conditions).

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QEP Notional Stock Awards

At the effective time of the merger, each QEP notional stock award under any QEP deferred compensation plan (other than deferred shares granted to any QEP employee) will become fully vested and converted into and deemed notionally invested in a number of shares of Diamondback common stock equal to the product of (i) the total number of shares of QEP common stock subject to such award immediately prior to the effective time of the merger multiplied by (ii) the exchange ratio. Such deferred compensation will be paid in cash promptly following the effective date of the merger (but not later than the time in which payment is required under the QEP deferred compensation plan).

QEP Employee Deferred Shares

At the effective time of the merger, any QEP employee deferred shares that are outstanding immediately prior to the effective time of the merger will be converted at the effective time of the merger into a number of time-based restricted shares of Diamondback common stock (rounded to the nearest whole share) equal to the product of (i) the total number of shares of QEP common stock subject to such award immediately prior to the effective time of the merger multiplied by (ii) the exchange ratio. Such awards will be subject to the same time-based and termination related vesting conditions as applied to the corresponding award of QEP employee deferred shares immediately prior to the effective time of the merger.

QEP Options

At the effective time of the merger, each option to purchase shares of QEP common stock that is outstanding immediately prior to the effective time of the merger, whether vested or unvested, will be automatically cancelled without any payment or other consideration required to be made in respect thereof.

For additional information regarding the treatment of QEP equity awards, see the section entitled “The Merger Agreement—Treatment of QEP Equity Awards in the Merger” beginning on page 113.

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Whether or not a quorum is present, the holders of a majority of the outstanding shares of QEP common stock who are present in person or by proxy and entitled to vote at the special meeting may adjourn the meeting from time to time, without notice other than by announcement at the meeting, to another date, place, if any, and time until a quorum is present. If the adjournment is for more than 30 days or if after the adjournment, a new record date is fixed for the adjourned meeting, QEP will provide a notice of the adjourned meeting to each stockholder of record entitled to vote at the meeting.

QEP’s bylaws also provide that the person presiding over any meeting of stockholders shall have the right and authority to convene and (for any or no reason) to recess and/or adjourn the meeting, to prescribe such rules, regulations and procedures and to do all such acts as, in the judgment of such presiding person, are appropriate for the proper conduct of the meeting. The presiding person at any meeting of stockholders, in addition to making any other determinations that may be appropriate to the conduct of the meeting, shall, if the facts warrant, determine and declare to the meeting that a matter or business was not properly brought before the meeting and if such presiding person should so determine, such presiding person shall so declare to the meeting and any such matter or business not properly brought before the meeting shall not be transacted or considered.

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Failure to provide the appropriate documentation may delay your admission to or prevent you from attending the QEP special meeting virtually on the QEP special meeting website. The QEP special meeting will commence promptly at the scheduled time and QEP stockholders may not be admitted to the virtual meeting following the start of the QEP special meeting.

Direct holders (holders of record). For shares of QEP common stock held directly, complete, sign, date and return the proxy card (or cast your vote by phone or the Internet as provided on the proxy card) or otherwise follow the voting instructions provided in this proxy statement/prospectus in order to ensure that all of your shares of QEP common stock are voted.

Shares in “street name.” For shares of QEP common stock held in “street name” through a broker, bank or other nominee, follow the instructions provided by your broker, bank or other nominee to vote your shares.

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If you are a beneficial owner of QEP common stock as of the close of business on the QEP record date, you must follow the instructions of your broker, bank or other nominee to revoke or change your voting instructions.

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If the merger qualifies as a reorganization, then U.S. holders (as defined in the section entitled “Material U.S. Federal Income Tax Consequences of the Merger” beginning on page 145) of shares of QEP common stock generally will not recognize any gain or loss for U.S. federal income tax purposes upon receipt of Diamondback common stock in exchange for QEP common stock in the merger (other than gain or loss, if any, with respect to any cash received in lieu of a fractional share of Diamondback common stock). The material U.S. federal income tax consequences of the merger are discussed in more detail in the section entitled “Material U.S. Federal Income Tax Consequences of the Merger” beginning on page 145. The discussion of the material U.S. federal income tax consequences contained in this proxy statement/prospectus is intended to provide only a general discussion and is not a complete analysis or description of all potential U.S. federal income tax consequences of the merger that may vary with, or are dependent on, individual circumstances. In addition, it does not address the effects of any foreign, state or local tax laws or any U.S. federal tax laws other than U.S. federal income tax laws.

TAX MATTERS ARE COMPLICATED AND THE TAX CONSEQUENCES OF THE MERGER WILL DEPEND ON THE FACTS OF YOUR OWN SITUATION. YOU SHOULD CONSULT YOUR OWN TAX ADVISOR AS TO THE SPECIFIC TAX CONSEQUENCES OF THE MERGER TO YOU IN YOUR PARTICULAR CIRCUMSTANCES.

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If you are a holder of book-entry shares representing eligible shares of QEP common stock (the “QEP book-entry shares”) which are held through the Depository Trust Company (“DTC”), the exchange agent will transmit to DTC or its nominees as soon as reasonably practicable on or after the closing date, the merger consideration, cash in lieu of any fractional shares of Diamondback common stock and any dividends and other distributions on the shares of Diamondback common stock issuable as merger consideration, in each case, that DTC has the right to receive.

If you are a holder of record of QEP book-entry shares which are not held through DTC, the exchange agent will deliver to you, as soon as practicable after the effective time of the merger, (i) a notice advising you of the effectiveness of the merger, (ii) a statement reflecting the aggregate whole number of shares of Diamondback common stock (which will be in uncertificated book-entry form) that you have a right to receive pursuant to the merger agreement and (iii) a check in the amount equal to the cash payable in lieu of any fractional shares of Diamondback common stock and dividends and other distributions on the shares of Diamondback common stock issuable to you as merger consideration.

No interest will be paid or accrued on any amount payable for shares of QEP common stock eligible to receive the merger consideration pursuant to the merger agreement.

For additional information on the exchange of QEP common stock for the merger consideration, see the section entitled “The Merger Agreement—Payment for Securities; Exchange” beginning on page 114.

Beginning with the first quarter of 2018, Diamondback has paid a dividend on the shares of Diamondback common stock. Prior to 2018, Diamondback did not pay dividends on its common stock. Any future Diamondback dividends will remain subject to approval by the Diamondback board and other considerations.

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Georgeson LLC

1290 Avenue of the Americas, 9^th Floor

New York, New York 10104

Stockholders, Banks and Brokers May Call Toll-Free (North America):

(800) 903-2897

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RISK FACTORS

In addition to the other information contained in or incorporated by reference into this proxy statement/prospectus, including the matters addressed in the section entitled “Cautionary Statement Regarding Forward-Looking Statements” beginning on page 49, QEP stockholders should carefully consider the following risks before deciding how to vote with respect to the merger proposal, the non-binding compensation advisory proposal and the adjournment proposal to be considered and voted on at the QEP special meeting. In addition, QEP stockholders should also read and consider the risks associated with each of the businesses of Diamondback and QEP because these risks will also affect the combined company. These risks can be found in Diamondback’s and QEP’s Annual Reports on Form 10-K for the year ended December 31, 2019, their subsequent reports on Form 10-Q and other documents they file with the SEC, in each case incorporated by reference into this proxy statement/prospectus. QEP stockholders should also read and consider the other information in this proxy statement/prospectus and the other documents incorporated by reference into this proxy statement/prospectus. For additional information, see the sections entitled “Where You Can Find More Information” and “Information Incorporated by Reference” each beginning on page 180.

Risk Factors Relating to the Merger

Because the exchange ratio is fixed and because the market price of Diamondback common stock will fluctuate, QEP stockholders cannot be certain of the precise value of the merger consideration they will receive in the merger.

If the merger is completed, at the effective time of the merger, each issued and outstanding eligible share of QEP common stock will be converted into the right to receive the merger consideration. The exchange ratio for the merger consideration is fixed at 0.050 of a share of Diamondback common stock for each share of QEP common stock (with certain exceptions described in this proxy statement/prospectus), and there will be no adjustment to the merger consideration for changes in the market price of Diamondback common stock or QEP common stock prior to the completion of the merger.

If the merger is completed, there will be a time lapse between each of the date of this proxy statement/prospectus, the date on which QEP stockholders vote to approve the QEP merger proposal and the date on which QEP stockholders entitled to receive the merger consideration actually receive the merger consideration. The market value of shares of Diamondback common stock will fluctuate, possibly materially, during and after these periods as a result of a variety of factors, including general market and economic conditions, changes in Diamondback’s businesses, operations and prospects and regulatory considerations and any impact of the ongoing COVID-19 pandemic. Such factors are difficult to predict and in many cases may be beyond the control of Diamondback and QEP. The actual value of any merger consideration received by QEP stockholders at the completion of the merger will depend on the market value of the shares of Diamondback common stock at that time. Consequently, at the time QEP stockholders decide whether to approve the merger proposal, they will not know the actual market value of any merger consideration they will receive when the merger is completed. For additional information about the merger consideration, see the sections entitled “The Merger—Consideration to QEP Stockholders” and “The Merger Agreement—Effect of the Merger on Capital Stock; Merger Consideration” beginning on page 60 and 112, respectively.

The merger may not be completed and the merger agreement may be terminated in accordance with its terms. Failure to complete the merger could negatively impact the price of shares of Diamondback common stock and the price of shares of QEP common stock, as well as Diamondback’s and QEP’s respective future businesses and financial results.

The merger is subject to a number of conditions that must be satisfied, including the approval by QEP stockholders of the merger agreement proposal, or, to the extent permitted by applicable law, waived, in each

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case prior to the completion of the merger. These conditions are described in the section entitled “The Merger Agreement—Conditions to the Completion of the Merger” beginning on page 139. These conditions to the completion of the merger, some of which are beyond the control of Diamondback and QEP, may not be satisfied or waived in a timely manner or at all, and, accordingly, the merger may be delayed or may not be completed.

In addition, if the merger is not completed by June 30, 2021, or, in certain instances, on or before September 30, 2021, either Diamondback or QEP may choose not to proceed with the merger by terminating the merger agreement, and the parties can mutually decide to terminate the merger agreement at any time, before or after stockholder approval. Further, either Diamondback or QEP may elect to terminate the merger agreement in certain other circumstances as further detailed in the section entitled “The Merger Agreement—Termination.”

If the transactions contemplated by the merger agreement are not completed for any reason, Diamondback’s and QEP’s respective ongoing businesses, financial condition and financial results may be adversely affected. Without realizing any of the benefits of having completed the transactions, Diamondback and QEP will be subject to a number of risks, including the following:

If the merger agreement is terminated and the QEP board seeks another merger or business combination, QEP may not be able to find a party willing to offer equivalent or more attractive consideration than the consideration Diamondback has agreed to provide in the merger, or that such other merger or business combination is completed. If the merger agreement is terminated under specified circumstances, QEP may be required to pay Diamondback a termination fee of $17 million. If the merger agreement is terminated because of a failure of QEP’s stockholders to approve the proposals required to complete the merger, QEP may be required to reimburse Diamondback for any reasonable, documented, out-of-pocket expenses paid or incurred by Diamondback in connection with the proposed transactions, in an amount not to exceed $7.5 million. For a description of these circumstances, see the section entitled “The Merger Agreement—Termination” beginning on page 140. In addition, any delay in completing the merger may significantly reduce the synergies and other benefits that Diamondback expects that the combined company may achieve if the merger is completed within the expected timeframe.

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QEP stockholders will have a reduced ownership and voting interest in the combined company after the merger compared to their current ownership in QEP and will exercise less influence over the combined company’s management.

Currently, QEP stockholders have the right to vote in the election of the QEP board and the power to approve or reject any matters requiring stockholder approval under Delaware law and the QEP organizational documents. Upon completion of the merger, each QEP stockholder who receives shares of Diamondback common stock in the merger will become a stockholder of Diamondback with a percentage ownership of Diamondback that is smaller than such QEP stockholder’s current percentage ownership of QEP. Based on the number of issued and outstanding shares of Diamondback common stock and QEP common stock as of January 15, 2021 and the exchange ratio of 0.050, after the merger QEP stockholders are expected to become owners of approximately 7% of the outstanding shares of Diamondback common stock, on a fully-diluted basis, without giving effect to (i) any shares of Diamondback common stock held by QEP stockholders prior to the completion of the merger or (ii) up to 10.63 million shares of Diamondback common stock to be issued in a previously announced pending acquisition by Diamondback of approximately 32,500 net acres in the Northern Midland Basin and certain related oil and gas assets pursuant to a definitive purchase and sale agreement with Guidon Operating LLC (“Guidon”) and certain of Guidon’s affiliates (the “Pending Guidon Acquisition”). Even if all former QEP stockholders voted together on all matters presented to Diamondback stockholders from time to time, the former QEP stockholders would exercise significantly less influence over on the management and policies of Diamondback post-merger than they now have on the management and policies of QEP.

Diamondback and QEP are subject to risks related to health epidemics and pandemics, including the ongoing COVID-19 pandemic, and it is difficult to predict what effect, if any, this might have on the merger.

Diamondback and QEP each face various risks related to public health issues, including epidemics, pandemics and other outbreaks, including the ongoing COVID-19 pandemic. The effects and potential effects of COVID-19 include, but are not limited to, its impact on general economic conditions, trade and financing markets, changes in customer behavior and continuity in business operations, all of which creates significant uncertainty. In addition, the pandemic has resulted in government authorities implementing significant and varied measures to contain the spread of COVID-19, including travel bans and restrictions, quarantines, shelter-in-place and stay-at-home orders, and business shutdowns. Government authorities may enact additional restrictions, or tighten existing measures, if COVID-19 continues to spread. These measures, as well as the COVID-19 pandemic broadly, may have a negative effect on the businesses of Diamondback or QEP prior to the consummation of the merger, and it is difficult to predict what effect the COVID-19 pandemic may have on the merger.

Required regulatory approvals may not be received, may take longer than expected to be received or may impose conditions that are not presently anticipated or cannot be met.

Completion of the merger is conditioned upon expiration or termination of any waiting period applicable to the merger under the HSR Act. Although each party has agreed to use its reasonable best efforts to ensure the prompt expiration or termination of any applicable waiting period under the HSR Act and to respond to and comply with any request for information from any government entity charged with enforcing, applying, administering or investigating the HSR Act or any other antitrust laws, there can be no assurance that the HSR approval will be obtained and that the other conditions to completing the merger will be satisfied. In addition, the governmental authorities from which the regulatory approvals are required may impose conditions on the completion of the merger or require changes to the terms of the merger agreement or other agreements to be entered into in connection with the merger agreement. Under the terms of the merger agreement, Diamondback has agreed to take any and all action necessary to obtain these governmental approvals; however Diamondback does not have to agree to any action that would reasonably be expected to have a material adverse effect on the post-closing business, financial condition or operations of Diamondback and its subsidiaries (including QEP and its subsidiaries), taken as a whole (with materiality calculated as if Diamondback and its subsidiaries were the

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same size as QEP and its subsidiaries) or that require Diamondback to take action (other than de minimis actions) other than with respect to QEP and its subsidiaries. The actions that Diamondback may be required to take include, among others, disposing of assets; terminating existing relationships, contractual rights or obligations; terminating any venture or other arrangement; creating new relationships, contractual rights or obligations; and making other changes or restructurings. These actions may adversely affect the business of Diamondback and its subsidiaries, including, post-merger, QEP. Diamondback and QEP cannot provide any assurance that these approvals will be obtained or that there will not be any adverse consequences to Diamondback’s or QEP’s business resulting from the failure to obtain these governmental approvals or from conditions that could be imposed in connection with obtaining these governmental approvals, including divestitures or other operating restrictions upon Diamondback, QEP, or their respective subsidiaries.

Completion of the merger is also conditioned upon the authorization for listing of Diamondback common stock to be issued in connection with the merger on the Nasdaq Global Select Market, or such other Nasdaq market on which shares of Diamondback common stock are then listed. Although Diamondback has agreed use its reasonable best efforts to take all action reasonably necessary to obtain the requisite stock exchange approval, there can be no assurance that such approval will be obtained and that the other conditions to completing the merger will be satisfied.

Such conditions or changes and the process of obtaining regulatory approvals could have the effect of delaying or impeding consummation of the merger or of imposing additional costs or limitations on Diamondback or QEP following completion of the merger, any of which might have an adverse effect on Diamondback or QEP following completion of the merger and may diminish the anticipated benefits of the merger. For additional information about the regulatory approvals process, see “The Merger—Regulatory Approvals” and “The Merger Agreement—HSR and Other Regulatory Approvals.”

If the merger does not qualify as a “reorganization” under Section 368(a) of the Code, the QEP stockholders may be subject to U.S. federal income tax upon the receipt of Diamondback common stock in the merger.

Diamondback and QEP intend for the merger to be treated as a “reorganization” within the meaning of Section 368(a) of the Code for U.S. federal income tax purposes. However, it is not a condition to Diamondback’s obligation or QEP’s obligation to complete the transactions that the merger qualifies as a “reorganization.” Moreover, neither Diamondback nor QEP intends to request any ruling from the IRS regarding any matters relating to the merger, and, consequently, there can be no assurance that the IRS will not assert, or that a court would not sustain, a position to the contrary to any of the positions set forth in this proxy statement/prospectus. If the IRS were to challenge the “reorganization” status of the merger successfully or the form or structure of the merger was changed in a manner such that it did not qualify as a “reorganization,” the tax consequences would differ from those set forth in this proxy statement/prospectus in the section entitled “Material U.S. Federal Income Tax Consequences of the Merger” beginning on page 145 and holders of QEP common stock could be subject to U.S. federal income tax upon the receipt of Diamondback common stock in the merger.

Diamondback and QEP will be subject to business uncertainties while the merger is pending, which could adversely affect their respective businesses.

Uncertainty about the effect of the merger on employees, industry contacts and business partners may have an adverse effect on Diamondback or QEP. These uncertainties may impair Diamondback’s or QEP’s ability to attract, retain and motivate key personnel until the merger is completed and for a period of time thereafter and could cause industry contacts, business partners and others that deal with Diamondback or QEP to seek to change their existing business relationships with Diamondback or QEP, respectively. Employee retention at QEP may be particularly challenging during the pendency of the merger, as employees may experience uncertainty about their roles with Diamondback following the merger. In addition, the merger agreement restricts Diamondback and QEP from entering into certain corporate transactions and taking other specified actions without the consent of

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the other party. These restrictions may prevent Diamondback and QEP from pursuing attractive business opportunities that may arise prior to the completion of the merger. For a description of the restrictive covenants to which Diamondback and QEP are subject, see the section entitled “The Merger Agreement—Interim Operations of QEP and Diamondback Pending the Merger.”

The merger agreement limits QEP’s ability to pursue alternatives to the merger, which may discourage certain other companies from making favorable alternative transaction proposals and, in specified circumstances, could require QEP to pay Diamondback a termination fee.

The merger agreement contains provisions that may discourage a third party from submitting a competing proposal to QEP that might result in greater value to QEP stockholders than the merger or, in the event that a third party competing proposal is made, a third party may propose to pay a lower per share price to acquire QEP than it might otherwise have proposed to pay. These provisions include a general prohibition on QEP soliciting or, subject to certain exceptions relating to the exercise of fiduciary duties by the QEP board, entering into discussions with any third party regarding any competing proposal. Further, even if the QEP board withholds, withdraws, qualifies or modifies its recommendation with respect to the QEP merger proposal, unless the merger agreement has been terminated in accordance with its terms, QEP will still have an obligation to submit the merger proposal to a vote by its stockholders. The merger agreement further provides that under specified circumstances, including after a change of recommendation by the QEP board and a subsequent termination of the merger agreement by Diamondback in accordance with its terms, QEP may be required to pay Diamondback a cash termination fee in the amount of $17 million. For additional information, see the sections entitled “The Merger Agreement—No Solicitation; Change of Recommendation” and “The Merger Agreement—Termination.”

Uncertainties associated with the merger may cause a loss of management personnel and other key employees, which could adversely affect the future business and operations of the combined company.

Diamondback and QEP are dependent on the experience and industry knowledge of their officers and other key employees to execute their business plans. Each company’s success until the merger and the combined company’s success after the merger will depend in part upon the ability of Diamondback and QEP to retain key management personnel and other key employees. Current and prospective employees of Diamondback and QEP may experience uncertainty about their roles within the combined company following the merger, which may have an adverse effect on the ability of each of Diamondback and QEP to attract or retain key management and other key personnel. Accordingly, no assurance can be given that the combined company will achieve the same success attracting or retaining key management personnel and other key employees as each of Diamondback and QEP have independently achieved prior to the merger.

Directors and executive officers of QEP may have interests in the merger that are different from, or in addition to, the interests of QEP stockholders.

Directors and executive officers of QEP may have interests in the merger that are different from, or in addition to, the interests of QEP stockholders generally. These interests include, among others, the treatment of outstanding equity and equity-based awards pursuant to the merger agreement, potential severance and other benefits upon a qualifying termination in connection with the merger, and rights to ongoing indemnification and insurance coverage. These interests are described in more detail in the section entitled “The Merger—Interests of QEP’s Directors and Executive Officers in the Merger.” The QEP board was aware of and carefully considered these interests of its directors and officers, among other matters, during its deliberations on the merits, terms, and structure of the merger, overseeing the negotiation of the merger, approving the merger agreement and the transactions contemplated thereby, including the merger, and in making its recommendation that QEP stockholders vote “FOR” approval of the merger proposal, “FOR” approval of the non-binding compensation advisory proposal and “FOR” the approval of the adjournment proposal.

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Diamondback and QEP will incur significant transaction and merger-related costs in connection with the merger, which may be in excess of those anticipated by Diamondback or QEP.

Each of Diamondback and QEP has incurred and expects to continue to incur a number of non-recurring costs associated with negotiating and completing the merger, combining the operations of the two companies and achieving desired synergies. These fees and costs have been, and will continue to be, substantial. The substantial majority of non-recurring expenses will consist of transaction costs related to the merger and include, among others, employee retention costs, fees paid to financial, legal and accounting advisors, severance and benefit costs, and filing fees.

Diamondback and QEP will also incur transaction fees and costs related to the integration of the companies, which may be substantial. Moreover, each company may incur additional unanticipated expenses in connection with the merger and the integration, including costs associated with any stockholder litigation related to the merger. Although Diamondback and QEP each expect that the elimination of duplicative costs, as well as the realization of other efficiencies related to the integration of the businesses, should allow Diamondback and QEP to offset integration-related costs over time, this net benefit may not be achieved in the near term, or at all. For additional information, see the risk factor entitled “The integration of QEP and Diamondback may not be as successful as anticipated, and Diamondback may not achieve the intended benefits or do so within the intended timeframe”below.

The costs described above, as well as other unanticipated costs and expenses, could have a material adverse effect on the financial condition and operating results of the combined company following the completion of the merger.

Completion of the merger may trigger change in control or other provisions in certain agreements to which QEP or its subsidiaries is a party.

The completion of the merger may trigger change in control or other provisions in certain agreements to which QEP or its subsidiaries is a party. If Diamondback and QEP are unable to negotiate waivers of those provisions, the counterparties may exercise their rights and remedies under such agreements, potentially terminating the agreement or seeking monetary damages. Additionally, even if Diamondback and QEP are able to negotiate waivers, the counterparties may require a fee for such waivers or seek to renegotiate the agreements on terms less favorable to the combined company.

Diamondback and its subsidiaries will have substantial indebtedness after giving effect to the merger, which may limit Diamondback’s financial flexibility and adversely affect its financial results.

Under the merger agreement, QEP’s outstanding debt (other than its existing credit facility) will remain outstanding, which debt, as of September 30, 2020 was approximately $1.6 billion and consisted of amounts outstanding under QEP’s senior notes. As of September 30, 2020, Diamondback had total long-term debt of approximately $5.8 billion, consisting primarily of the amounts outstanding under its revolving credit facility, its senior unsecured notes, the notes issued by its subsidiary Energen Corporation, the senior notes issued by Diamondback’s publicly traded subsidiaries, Viper and Rattler, and the amounts outstanding under Viper’s and Rattler’s revolving credit facilities.

Diamondback’s pro forma indebtedness as of September 30, 2020, assuming consummation of the merger had occurred on such date and QEP’s senior notes remain outstanding, would have been approximately $7.4 billion, representing an increase in comparison to Diamondback’s indebtedness on a recent historical basis. Diamondback believes that post-merger it will retain its investment grade credit ratings and retire the combined company’s pro forma debt at a faster rate than either company would have been able to do absent the merger. However, any increase in Diamondback’s indebtedness could have adverse effects on its financial condition and results of operations, including:

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Diamondback believes that the combined company will have flexibility to repay, refinance, repurchase, redeem, exchange or otherwise terminate large portions of its outstanding debt obligations. However, there can be no guarantee that Diamondback would be able to execute such refinancings on favorable terms or at all, and a high level of indebtedness increases the risk that Diamondback may default on its debt obligations, including from the debt obligations of QEP. Diamondback’s ability to meet its debt obligations and to reduce its level of indebtedness depends on its future performance. Diamondback’s future performance depends on many factors independent of the merger, some of which are beyond its control, such as general economic conditions and oil and natural gas prices. Diamondback may not be able to generate sufficient cash flows to pay the interest on its debt, and future working capital, borrowings or equity financing may not be available to pay or refinance such debt.

The opinion of QEP’s financial advisor will not reflect changes in circumstances between the signing of the merger agreement and the completion of the merger.

QEP has received an opinion from Evercore, its financial advisor, in connection with the signing of the merger agreement, but has not obtained an updated opinion from such financial advisor as of the date of this proxy statement/prospectus. Changes in the operations and prospects of QEP, general market and economic conditions and other factors that may be beyond the control of Diamondback or QEP, and on which QEP’s financial advisor’s opinion was based, may significantly alter the value of Diamondback or QEP or the prices of the shares of Diamondback common stock or of the shares of QEP common stock by the time the merger is completed. The opinion does not speak as of the time the merger will be completed or as of any date other than the date of such opinion. The QEP board’s recommendation that QEP stockholders vote “FOR” approval of the merger proposal, the non-binding compensation advisory proposal and the adjournment proposal, however, is made as of the date of this proxy statement/prospectus. Because QEP does not currently anticipate asking its financial advisor to update its opinion, the opinion will not address the fairness of the merger consideration or the exchange ratio, as applicable, from a financial point of view at the time the merger is completed or at the time of the QEP board’s recommendation.

For a description of the opinion that QEP received from its financial advisor, see the section entitled “The Merger—Opinion of QEP’s Financial Advisor.” A copy of the opinion of Evercore is attached as Annex B to this proxy statement/prospectus and is incorporated by reference herein in its entirety.

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Lawsuits have been filed against QEP, Diamondback, Merger Sub and the members of the QEP board in connection with the merger and additional lawsuits may be filed in the future. An adverse ruling in any such lawsuit could result in an injunction preventing the completion of the merger and/or substantial costs to Diamondback and QEP.

Securities class action lawsuits and derivative lawsuits are often brought against public companies that have entered into acquisition, merger or other business combination agreements like the merger agreement. Even if such a lawsuit is without merit, defending against these claims can result in substantial costs and divert management time and resources. An adverse judgment could result in monetary damages, which could have a negative impact on Diamondback’s and QEP’s respective liquidity and financial condition.

As of February 8, 2021, seven individual lawsuits have been filed by purported QEP stockholders in United States District Courts in connection with the proposed merger. All seven lawsuits name QEP and the members of the QEP board as defendants, and two of the seven lawsuits name Diamondback and Merger Sub as defendants. The complaints allege, among other things, that the registration statements relating to the merger on Form S-4 filed by Diamondback on January 22, 2021, and as amended on Form S-4/A filed on February 3, 2021, fail to provide certain allegedly material information concerning the proposed merger in violation of Sections 14(a) and 20(a) of the Exchange Act and Rule 14a-9 promulgated thereunder. Among other remedies, the plaintiffs seek to enjoin the completion of the proposed merger, a recission of the completed merger or rescissory damages, an accounting of damages suffered by the plaintiff, an award of plaintiff’s expenses and attorney’s fees, and other relief.

Each of Diamondback and QEP believes that the allegations in the complaints are without merit. Additional lawsuits arising out of the merger may also be filed in the future. See the section entitled “The Merger—Litigation Relating to the Merger” for more information about litigation related to the merger that has been commenced prior to the date of this proxy statement/prospectus.

One of the conditions to the closing of the merger is that no injunction by any governmental entity having jurisdiction over Diamondback, QEP or Merger Sub has been entered and continues to be in effect and no law has been adopted, in either case that prohibits the closing of the merger. Consequently, if a plaintiff is successful in obtaining an injunction prohibiting completion of the merger, that injunction may delay or prevent the merger from being completed within the expected timeframe or at all, which may adversely affect Diamondback’s and QEP’s respective business, financial position and results of operations.

Additionally, there can be no assurance that any of the defendants will be successful in the outcome of the lawsuits filed thus far or any potential future lawsuits. The defense or settlement of any lawsuit or claim that remains unresolved at the time the merger is completed may adversely affect Diamondback’s or QEP’s business, financial condition, results of operations and cash flows.

Shares of Diamondback common stock received by QEP stockholders as a result of the merger will have different rights from shares of QEP common stock.

Upon completion of the merger, QEP stockholders will no longer be stockholders of QEP, and QEP stockholders who receive the merger consideration will become Diamondback stockholders, and their rights as Diamondback stockholders will be governed by the terms of Diamondback’s charter and bylaws. There will be important differences between the current rights of QEP stockholders and the rights to which such stockholders will be entitled as Diamondback stockholders. For a discussion of the different rights associated with shares of Diamondback common stock as compared to QEP common stock, see the section entitled “Comparison of Rights of Stockholders of Diamondback and Stockholders of QEP.”

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The exclusive forum provision contained in Diamondback’s charter could limit its stockholders’ ability to obtain a favorable judicial forum for disputes with Diamondback or its directors, officers or other employees.

Diamondback’s charter provides that, unless Diamondback consents in writing to the selection of an alternative forum, the sole and exclusive forum for (i) any derivative action or proceeding brought on behalf of Diamondback, (ii) any action asserting a claim of breach of a fiduciary duty owed by any director, officer or other employee of Diamondback to Diamondback or its stockholders, (iii) any action asserting a claim against Diamondback or any director or officer or other employee of Diamondback arising pursuant to any provision of the DGCL or Diamondback’s charter or bylaws or (iv) any action asserting a claim against Diamondback or any director or officer or other employee of Diamondback governed by the internal affairs doctrine shall be the Court of Chancery of the State of Delaware.

To the fullest extent permitted by law, this exclusive forum provision applies to state and federal law claims, including claims under the federal securities laws, including the Securities Act and the Exchange Act, although Diamondback stockholders will not be deemed to have waived Diamondback’s compliance with the federal securities laws and the rules and regulations thereunder. The enforceability of similar choice of forum provisions in other companies’ governing documents has been challenged in legal proceedings, and it is possible that, in connection with claims arising under federal securities laws or otherwise, a court could find the exclusive forum provision contained in Diamondback’s charter to be inapplicable or unenforceable.

This exclusive forum provision may limit the ability of a stockholder, including a former QEP stockholder who becomes a Diamondback stockholder after the merger is completed, to bring a claim in a judicial forum of its choosing for disputes with Diamondback or its directors, officers or other employees, which may discourage lawsuits against Diamondback and its directors, officers and other employees. Alternatively, if a court were to find this exclusive forum provision inapplicable to, or unenforceable in respect of, one or more of the specified types of actions or proceedings described above, Diamondback may incur additional costs associated with resolving such matters in other jurisdictions, which could negatively affect Diamondback’s business, results of operations and financial condition. In addition, stockholders who do bring a claim in a state or federal court located within the State of Delaware could face additional litigation costs in pursuing any such claim, particularly if they do not reside in or near Delaware. In addition, Court of Chancery of the State of Delaware may reach different judgments or results than would other courts, including courts where a stockholder would otherwise choose to bring the action, and such judgments or results may be more favorable to Diamondback than to its stockholders.

Diamondback or QEP may waive one or more of the closing conditions without re-soliciting stockholder approval.

Diamondback or QEP may determine to waive, in whole or part, one or more of the conditions to closing the merger prior to Diamondback or QEP, as the case may be, being obligated to consummate the merger. Each of Diamondback and QEP currently expects to evaluate the materiality of any waiver and its effect on its respective stockholders in light of the facts and circumstances at the time, to determine whether any amendment of this proxy statement/prospectus or any re-solicitation of proxies is required in light of such waiver. Any determination whether to waive any condition to the merger, re-solicit stockholder approval or amend or supplement this proxy statement/prospectus as a result of a waiver will be made by Diamondback or QEP at the time of such waiver based on the facts and circumstances as they exist at that time.

QEP stockholders are not entitled to appraisal rights in connection with the merger.

Appraisal rights are statutory rights that enable stockholders to dissent from certain extraordinary transactions, such as certain mergers, and to demand that the corporation pay the fair value for their shares as determined by a court in a judicial proceeding instead of receiving the consideration offered to stockholders in connection with the applicable transaction. Under the DGCL, holders of shares of QEP common stock will not have rights to an appraisal of the fair value of their shares in connection with the merger. See “The Merger—No Appraisal Rights in the Merger” beginning on page 108 for additional information.

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Risk Factors Relating to Diamondback Following the Merger

The integration of QEP into Diamondback may not be as successful as anticipated, and Diamondback may not achieve the intended benefits or do so within the intended timeframe.

The merger involves numerous operational, strategic, financial, accounting, legal, tax and other risks, potential liabilities associated with the acquired businesses, and uncertainties related to design, operation and integration of QEP’s internal control over financial reporting. Difficulties in integrating QEP into Diamondback may result in QEP performing differently than expected, operational challenges, or the failure to realize anticipated expense-related efficiencies. Potential difficulties that may be encountered in the integration process include, among others:

Additionally, the success of the merger will depend, in part, on Diamondback’s ability to realize the anticipated benefits and cost savings from combining Diamondback’s and QEP’s businesses, including operational and other synergies that Diamondback believes the combined company will achieve, discussed in more detail under the heading “The Merger—Diamondback’s Rationale for the Merger.” The anticipated benefits and cost savings of the merger may not be realized fully or at all, may take longer to realize than expected, or could have other adverse effects that Diamondback does not currently foresee.

Diamondback’s results may suffer if it does not effectively manage its expanded operations following the merger.

The success of the merger will depend, in part, on Diamondback’s ability to realize the anticipated benefits and cost savings from combining Diamondback’s and QEP’s businesses, including the need to integrate the operations and business of QEP into its existing business in an efficient and timely manner, to combine systems and management controls and to integrate relationships with customers, vendors, industry contacts and business partners.

The anticipated benefits and cost savings of the merger may not be realized fully or at all, may take longer to realize than expected or could have other adverse effects that Diamondback does not currently foresee. Some of the assumptions that Diamondback has made, such as the achievement of operating synergies, may not be realized. There could also be unknown liabilities and unforeseen expenses associated with the merger that were not discovered in the due diligence review conducted by each company prior to entering into the merger agreement.

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The unaudited pro forma condensed combined financial information and QEP’s unaudited forecasted financial information included in this proxy statement/prospectus is presented for illustrative purposes only and does not represent the actual financial position or results of operations of the combined company following the completion of the merger. Future results of Diamondback or QEP may differ, possibly materially, from the unaudited pro forma condensed combined financial information and QEP’s unaudited forecasted financial information presented in this proxy statement/prospectus.

The unaudited pro forma condensed combined financial statements and QEP’s unaudited forecasted financial information contained in this proxy statement/prospectus is presented for illustrative purposes only, contains a variety of adjustments, assumptions and preliminary estimates and does not represent the actual financial position or results of operations of Diamondback and QEP prior to the merger or that of the combined company following the merger. Specifically, the unaudited pro forma condensed combined financial statements do not reflect the effect of any potential acquisitions (including the Pending Guidon Acquisition) or divestitures that may occur prior to or subsequent to the completion of the merger, integration costs or any changes in Diamondback’s debt to capitalization ratio following the completion of the merger. For additional information, see the section entitled “Unaudited Pro Forma Condensed Combined Financial Statements.”In addition, the merger and post-merger integration process may give rise to unexpected liabilities and costs, including costs associated with the defense and resolution of transaction-related litigation or other claims. Unexpected delays in completing the merger or in connection with the post-merger integration process may significantly increase the related costs and expenses incurred by Diamondback. The actual financial positions and results of operations of Diamondback and QEP prior to the merger and that of the combined company following the merger may be different, possibly materially, from the unaudited pro forma condensed combined financial statements or QEP’s unaudited forecasted financial information included in this proxy statement/prospectus. In addition, the assumptions used in preparing the unaudited pro forma condensed combined financial statements and QEP’s unaudited forecasted financial information included in this proxy statement/prospectus may not prove to be accurate and may be affected by other factors. Any significant changes in the market price of Diamondback common stock may cause a significant change in the purchase price used for Diamondback’s accounting purposes and the unaudited pro forma condensed combined financial statements contained in this proxy statement/prospectus.

The merger may not be accretive, and may be dilutive, to Diamondback’s earnings per share, which may negatively affect the market price of Diamondback common stock.

Because shares of Diamondback common stock will be issued in the merger, it is possible that, although Diamondback currently expects the merger to be accretive to earnings per share, the merger may be dilutive to Diamondback’s earnings per share, which could negatively affect the market price of Diamondback common stock.

In connection with the completion of the merger, based on the number of issued and outstanding shares of QEP common stock as of January 15, 2021 and the number of outstanding QEP equity awards currently estimated to be payable in Diamondback common stock following the merger, Diamondback will issue up to approximately shares of Diamondback common stock. The issuance of these new shares of Diamondback common stock could have the effect of depressing the market price of Diamondback common stock, through dilution of earnings per share or otherwise. Any dilution of, or delay of any accretion to, Diamondback’s earnings per share could cause the price of shares of Diamondback common stock to decline or increase at a reduced rate.

Furthermore, former QEP stockholders and current Diamondback stockholders may not wish to continue to invest in the additional operations of the combined company, or for other reasons may wish to dispose of some or all of their interests in the combined company, and as a result may seek to sell their shares of Diamondback common stock following, or in anticipation of, completion of the merger. The merger agreement does not restrict the ability of former QEP stockholders to sell such shares of Diamondback common stock following completion

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of the merger. Therefore, these sales (or the perception that these sales may occur), coupled with the increase in the outstanding number of shares of Diamondback common stock, may affect the market for, and the market price of, Diamondback common stock in an adverse manner.

If the merger is completed and stockholders of Diamondback, including former QEP stockholders, sell substantial amounts of Diamondback common stock in the public market following the consummation of the merger, the market price of Diamondback common stock may decrease. These sales might also make it more difficult for Diamondback to raise capital by selling equity or equity-related securities at a time and price that it otherwise would deem appropriate.

The market price of Diamondback common stock will continue to fluctuate after the merger, and may decline if the benefits of the merger do not meet the expectations of financial analysts.

Upon completion of the merger, holders of QEP common stock who receive merger consideration will become holders of shares of Diamondback common stock. The market price of Diamondback common stock may fluctuate significantly following completion of the merger and holders of QEP common stock could lose some or all of the value of their investment in Diamondback common stock. In addition, the stock market has recently experienced significant price and volume fluctuations which could, if such fluctuations continue to occur, have a material adverse effect on the market for, or liquidity of, the Diamondback common stock, regardless of Diamondback’s actual operating performance.

The market price of Diamondback common stock may be affected by factors different from those that historically have affected QEP common stock or Diamondback common stock.

Upon completion of the merger, holders of QEP common stock who receive the merger consideration will become holders of Diamondback common stock. The businesses of Diamondback differ from those of QEP in certain respects, and, accordingly, the financial position or results of operations and/or cash flows of Diamondback after the merger, as well as the market price of Diamondback common stock, may be affected by factors different from those currently affecting the financial position or results of operations and/or cash flows of QEP and Diamondback as independent standalone companies. In particular, following the completion of the merger, QEP will be part of a larger company, which means that decisions affecting QEP may be made in respect of the larger combined business as a whole rather than the QEP businesses individually. For a discussion of the businesses of Diamondback and QEP and of some important factors to consider in connection with those businesses, see the section entitled “Information About the Companies” and the documents incorporated by reference in the section entitled “Where You Can Find More Information,” including, in particular, in the sections entitled “Risk Factors” in each of Diamondback’s and QEP’s Annual Report on Form 10-K for the year ended December 31, 2019 and Quarterly Reports on Form 10-Q for the quarters ended March 31, 2020, June 30, 2020 and September 30, 2020.

Following the completion of the merger, Diamondback may incorporate QEP’s hedging activities into Diamondback’s business, and Diamondback may be exposed to additional commodity price risks arising from such hedges.

To mitigate its exposure to changes in commodity prices, QEP hedges oil and natural gas prices from time to time, primarily through the use of certain derivative instruments. If Diamondback assumes QEP’s existing derivative instruments or if QEP enters into additional derivative instruments prior to the completion of the merger, Diamondback will bear the economic impact of the contracts following the completion of the merger. Actual crude oil and natural gas prices may differ from the combined company’s expectations and, as a result, such derivative instruments may have a negative impact on Diamondback’s business.

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The combined company may record goodwill and other intangible assets that could become impaired and result in material non-cash charges to the results of operations of the combined company in the future.

The merger will be accounted for as an acquisition by Diamondback in accordance with GAAP. Under the acquisition method of accounting, the assets and liabilities of QEP and its subsidiaries will be recorded, as of completion of the merger, at their respective fair values and added to those of Diamondback. The reported financial condition and results of operations of Diamondback for the periods after completion of the merger will reflect QEP balances and results after completion of the merger but will not be restated retroactively to reflect the historical financial position or results of operations of QEP and its subsidiaries for periods prior to the merger. For additional information, see the section entitled “Unaudited Pro Forma Condensed Combined Financial Statements.”

Under the acquisition method of accounting, the total purchase price will be allocated to QEP’s tangible assets and liabilities and identifiable intangible assets based on their fair values as of the date of completion of the merger. The excess of the purchase price over those fair values will be recorded as goodwill. Diamondback and QEP expect that the merger may result in the creation of goodwill based upon the application of the acquisition method of accounting. To the extent goodwill or intangibles are recorded and the values become impaired, the combined company may be required to recognize material non-cash charges relating to such impairment. The combined company’s operating results may be significantly impacted from both the impairment and underlying trends in the business that triggered the impairment.

The combined company may not be able to retain customers or suppliers, and customers or suppliers may seek to modify contractual obligations with the combined company, either of which could have an adverse effect on the combined company’s business and operations. Third parties may terminate or alter existing contracts or relationships with Diamondback or QEP as a result of the merger.

As a result of the merger, the combined company may experience impacts on relationships with customers and suppliers that may harm the combined company’s business and results of operations. Certain customers or suppliers may seek to terminate or modify contractual obligations following the merger whether or not contractual rights are triggered as a result of the merger. There can be no guarantee that customers and suppliers will remain with or continue to have a relationship with the combined company or do so on the same or similar contractual terms following the merger. If any customers or suppliers seek to terminate or modify contractual obligations or discontinue their relationships with the combined company, then the combined company’s business and results of operations may be harmed. If the combined company’s suppliers were to seek to terminate or modify an arrangement with the combined company, then the combined company may be unable to procure necessary supplies or services from other suppliers in a timely and efficient manner and on acceptable terms, or at all.

QEP also has contracts with vendors, landlords, licensors and other business partners which may require QEP to obtain consent from these other parties in connection with the merger. If these consents cannot be obtained, the combined company may suffer a loss of potential future revenue, incur costs and/or lose rights that may be material to the business of the combined company. In addition, third parties with whom Diamondback or QEP currently have relationships may terminate or otherwise reduce the scope of their relationship with either party in anticipation of the merger. Any such disruptions could limit the combined company’s ability to achieve the anticipated benefits of the merger. The adverse effect of any such disruptions could also be exacerbated by a delay in the completion of the merger or by a termination of the merger agreement.

The financial forecasts relating to Diamondback and QEP prepared in connection with the merger may not be realized, which may adversely affect the market price of Diamondback common stock following the completion of the merger.

This proxy statement/prospectus includes certain financial forecasts considered by Diamondback and QEP in connection with their respective businesses. None of the financial forecasts prepared by QEP or Diamondback

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were prepared with a view towards public disclosure or compliance with the published guidelines of the SEC, Financial Accounting Standards Board or the American Institute of Certified Public Accountants. These forecasts are inherently based on various estimates and assumptions that are subject to the judgment of those preparing them and, in the view of QEP’s and Diamondback’s management, were prepared on a reasonable basis, reflecting the best available estimates and judgments as of the date they were prepared. These forecasts are also subject to significant economic, competitive, industry and other uncertainties and contingencies, all of which are difficult or impossible to predict and many of which are beyond the control of QEP and Diamondback. The financial forecasts are not fact and should not be relied upon as being necessarily indicative of future results and readers are cautioned not to place undue reliance on the information provided. Important factors that may affect the actual results of QEP or Diamondback and cause the internal financial forecasts to not be achieved include risks and uncertainties relating to QEP’s or Diamondback’s businesses, industry performance, the regulatory environment, general business and economic conditions and other factors described under the section entitled “Cautionary Statement Regarding Forward-Looking Statements” in this proxy statement/prospectus.

In addition, the financial forecasts also reflect assumptions that are subject to change and do not reflect revised prospects for QEP’s and Diamondback’s businesses, changes in general business or economic conditions or any other transaction or event that has occurred or that may occur and that was not anticipated at the time the financial forecasts were prepared. In addition, since such financial forecasts cover multiple years, the information by its nature becomes less predictive with each successive year. There can be no assurance that QEP’s and Diamondback’s financial condition or results of operations will be consistent with those set forth in such forecasts.

Declaration, payment and amounts of dividends, if any, distributed to stockholders of Diamondback will be uncertain.

Although Diamondback has paid cash dividends on Diamondback common stock in the past, the Diamondback board may determine not to declare dividends in the future or may reduce the amount of dividends paid in the future. Any payment of future dividends will be at the discretion of the Diamondback board and will depend on Diamondback’s results of operations, financial condition, cash requirements, future prospects and other considerations that the Diamondback board deems relevant.

Risks Relating to Diamondback’s Business.

You should read and consider risk factors specific to Diamondback’s businesses that will also affect the combined company after the completion of the merger. These risks are described in Part I, Item 1A of Diamondback’s Annual Report on Form 10-K for the fiscal year ended December 31, 2019, and in Part II, Item 1A of Diamondback’s Quarterly Reports on Form 10-Q for the quarters ended March 31, 2020, June 30, 2020, and September 30, 2020, and in other documents that are incorporated by reference herein. For the location of information incorporated by reference in this proxy statement/prospectus, see the section entitled “Where You Can Find More Information.”

Risks Relating to QEP’s Business.

You should read and consider risk factors specific to QEP’s businesses that will also affect the combined company after the completion of the merger. These risks are described in Part I, Item 1A of QEP’s Annual Report on Form 10-K for the fiscal year ended December 31, 2019, and in Part II, Item 1A of QEP’s Quarterly Reports on Form 10-Q for the quarters ended March 31, 2020, June 30, 2020 and September 30, 2020, and in other documents that are incorporated by reference herein. For the location of information incorporated by reference in this proxy statement/prospectus, see the section entitled “Where You Can Find More Information.”

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CAUTIONARY STATEMENT REGARDING FORWARD-LOOKING STATEMENTS

This proxy statement/prospectus, and the documents to which Diamondback and QEP refer you in this proxy statement/prospectus, as well as oral statements made or to be made by Diamondback and QEP, include certain “forward-looking statements” within the meaning of Section 27A of the Securities Act and Section 21E of the Exchange Act. All statements, other than statements of historical fact, included in this proxy statement/prospectus that address activities, events or developments that Diamondback or QEP expects, believes or anticipates will or may occur in the future are forward-looking statements. Words such as “estimate,” “project,” “predict,” “believe,” “expect,” “anticipate,” “potential,” “create,” “intend,” “could,” “may,” “foresee,” “plan,” “will,” “guidance,” “look,” “outlook,” “goal,” “future,” “assume,” “forecast,” “build,” “focus,” “work,” “continue” or the negative of such terms or other variations thereof and words and terms of similar substance used in connection with any discussion of future plans, actions, or events identify forward-looking statements. However, the absence of these words does not mean that the statements are not forward-looking. These forward-looking statements include, but are not limited to, statements regarding the merger, pro forma descriptions of the combined company and its operations, including pro forma financial statements and related adjustments and pro forma reserves, integration and transition plans, synergies, opportunities and anticipated future performance. There are a number of risks and uncertainties that could cause actual results to differ materially from the forward-looking statements included in this proxy statement/prospectus. These include:

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Such factors are difficult to predict and in many cases may be beyond the control of Diamondback and QEP. Diamondback’s and QEP’s forward-looking statements are based on assumptions that Diamondback and QEP, respectively, believe to be reasonable but that may not prove to be accurate. Consequently, all of the forward-looking statements Diamondback and QEP make in this proxy statement/prospectus are qualified by the information contained or incorporated by reference herein, including the information contained under this heading and the information detailed in Diamondback’s Annual Report on Form 10-K for the fiscal year ended December 31, 2019, Quarterly Reports on Form 10-Q for the quarterly periods ended March 31, 2020, June 30, 2020 and September 30, 2020, Current Reports on Form 8-K and other filings Diamondback makes with the SEC, which are incorporated herein by reference, and in QEP’s Annual Report on Form 10-K for the fiscal year ended December 31, 2019, Quarterly Reports on Form 10-Q for the quarterly periods ended March 31, 2020, June 30, 2020 and September 30, 2020, Current Reports on Form 8-K and other filings QEP makes with the SEC, which are incorporated herein by reference. For additional information, see the sections entitled “Risk Factors,” “Where You Can Find More Information” and “Information Incorporated by Reference” beginning on pages 35 and 180, respectively.

Diamondback and QEP undertake no obligation to update any forward-looking statements or to publicly release the result of any revisions to any such forward-looking statements that may be made to reflect events or circumstances that occur, or which they become aware of, except as required by applicable law or regulation. Readers are cautioned not to place undue reliance on these forward-looking statements, which speak only as of the date hereof.

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INFORMATION ABOUT THE COMPANIES

Diamondback Energy, Inc.

500 West Texas

Suite 1200

Midland, Texas 79701

Phone: (432) 221-7400

Diamondback is an independent oil and gas company currently focused on the acquisition, development, exploration and exploitation of unconventional, onshore oil and natural gas reserves in the Permian Basin in West Texas. Diamondback was incorporated in Delaware on December 30, 2011. Diamondback operates in two business segments: (i) the upstream segment, which is engaged in the acquisition, development, exploration and exploitation of unconventional, onshore oil and natural gas reserves in the Permian Basin in West Texas and (ii) through its publicly-traded subsidiary, Rattler Midstream LP, the midstream operations segment, which is focused on ownership, operation, development and acquisition of the midstream infrastructure assets in the Midland and Delaware Basins of the Permian Basin. Diamondback’s corporate headquarters are located in Midland, Texas and Diamondback common stock trades on the Nasdaq Global Select Market under the ticker symbol “FANG.”

QEP Resources, Inc.

1050 17^th Street, Suite 800

Denver, Colorado 80265

Phone: (303) 672-6900

QEP is an independent crude oil and natural gas exploration and production company with operations in two regions of the United States: the Southern Region (primarily in Texas) and the Northern Region (primarily in North Dakota). QEP’s corporate headquarters are located in Denver, Colorado and shares of QEP common stock trade on the NYSE under the ticker symbol “QEP.”

Bohemia Merger Sub Inc.

c/o Diamondback Energy, Inc.

500 West Texas

Suite 1200

Midland, Texas 79701

Phone: (432) 221-7400

Bohemia Merger Sub Inc., or Merger Sub, is a direct, wholly owned subsidiary of Diamondback. Upon the completion of the merger, Merger Sub will cease to exist. Merger Sub was incorporated in Delaware on December 18, 2020, for the sole purpose of effecting the merger.

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SPECIAL MEETING OF QEP STOCKHOLDERS

This proxy statement/prospectus is being provided to the QEP stockholders as part of a solicitation of proxies by the QEP board for use at the special meeting to be held at the time and place specified below and at any properly convened meeting following an adjournment or postponement thereof. This proxy statement/prospectus provides QEP stockholders with information they need to know to be able to vote or instruct their vote to be cast at the special meeting.

Date, Time and Place

The QEP special meeting will be held virtually via the Internet on March 16, 2021, at 8:00 am, Mountain Time.

In light of the public health concerns regarding the ongoing COVID-19 pandemic, the QEP special meeting will be held in a virtual meeting format only, via live webcast, and there will not be a physical meeting location. You will be able to attend the QEP special meeting online and vote your shares electronically at the meeting by visiting www.virtualshareholdermeeting.com/QEP2021SM (the “QEP special meeting website”). To attend the meeting on the QEP special meeting website, please follow the instructions provided on the enclosed proxy card and the QEP special meeting website.

Purpose of the QEP Special Meeting

The purpose of the QEP special meeting is to consider and vote on:

QEP will transact no other business at the QEP special meeting.

Recommendation of the QEP Board of Directors

The QEP board unanimously recommends that QEP stockholders vote:

For additional information on the recommendation of the QEP board, see the section entitled “QEP Stockholder Proposals” and “The Merger—Recommendation of the QEP Board of Directors and QEP’s Reasons for the Merger” beginning on page 58 and 77, respectively.

Record Date and Outstanding Shares of QEP Common Stock

Only holders of record of issued and outstanding shares of QEP common stock as of the close of business on February 5, 2021, the record date for the QEP special meeting (the “QEP record date”), are entitled to notice of, and to vote at, the QEP special meeting or any adjournment or postponement of the QEP special meeting.

As of the close of business on the QEP record date, there were 242,565,821.875 shares of QEP common stock issued and outstanding and entitled to vote at the QEP special meeting. You may cast one vote for each share of QEP common stock that you held as of the close of business on the QEP record date.

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A complete list of QEP stockholders entitled to vote at the QEP special meeting will be available for inspection at QEP’s principal office at 1050 17^th Street, Suite 800, Denver, Colorado 80265 during regular business hours beginning with the tenth day prior to the QEP special meeting and continuing through the QEP special meeting and during the QEP special meeting on March 16, 2021. A complete list of QEP stockholders entitled to vote at the QEP special meeting will also be posted on the QEP special meeting website during the same period.

Quorum; Abstentions and Broker Non-Votes

A quorum of QEP stockholders is necessary to hold a valid meeting. The presence at the special meeting of the holders of a majority of the outstanding shares of QEP common stock entitled to vote generally in the election of directors, present in person or represented by proxy, constitutes a quorum. Virtual attendance at the QEP special meeting constitutes presence in person for purposes of the quorum requirements under QEP’s bylaws. If you submit a properly executed proxy card, even if you do not vote for one or both of the proposals or vote to “ABSTAIN” in respect of one or both of the proposals, your shares of QEP common stock will be counted for purposes of determining whether a quorum is present for the transaction of business at the QEP special meeting.

QEP common stock held in “street name” with respect to which the beneficial owner fails to give voting instructions to the broker, bank or other nominee, and QEP common stock with respect to which the beneficial owner otherwise fails to vote, will not be considered present and entitled to vote at the QEP special meeting for the purpose of determining the presence of a quorum.

A broker non-vote will result if your broker, bank or other nominee returns a proxy but does not provide instruction as to how shares should be voted on a particular matter. Under the current rules of the NYSE, brokers, banks or other nominees do not have discretionary authority to vote on any of the proposals to be considered at the QEP special meeting. Because the only proposals for consideration at the QEP special meeting are nondiscretionary proposals, it is not expected that there will be any broker non-votes at the QEP special meeting. However, if there are any broker non-votes, the shares will not be considered present and entitled to vote at the QEP special meeting for the purpose of determining the presence of a quorum.

Executed but unvoted proxies will be voted in accordance with the recommendations of the QEP board.

Required Votes

Approval of the merger proposal requires the affirmative vote of a majority of the outstanding shares of QEP common stock entitled to vote on the proposal. Abstentions and broker non-votes will have the same effect as a vote “AGAINST” the proposal. Failure to vote on the merger proposal will have the same effect as a vote “AGAINST” the merger proposal.

Approval of the non-binding compensation advisory proposal requires the affirmative vote of a majority of the shares of QEP common stock present in person or represented by proxy at the QEP special meeting and entitled to vote on the proposal. Abstentions will have the same effect as a vote “AGAINST” the proposal, and failures to vote or broker non-votes will have no effect on the outcome of the vote.

Approval of the adjournment proposal requires the affirmative vote of a majority of the shares of QEP common stock present in person or represented by proxy at the QEP special meeting and entitled to vote on the proposal. Abstentions will have the same effect as a vote “AGAINST” the proposal, and failures to vote or broker non-votes will have no effect on the outcome of the vote.

The merger proposal, the non-binding compensation advisory proposal and the adjournment proposal are described in the section entitled “QEP Stockholder Proposals” beginning on page 58.

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Methods of Voting

QEP stockholders, whether holding shares directly as stockholders of record or beneficially in “street name,” may vote on the Internet by going to the web address provided on the enclosed proxy card and following the instructions for Internet voting, by phone using the toll-free phone number listed on the enclosed proxy card, or by completing, signing, dating and returning the enclosed proxy card in the postage-paid envelope provided.

QEP stockholders of record may vote their shares in person by ballot at the QEP special meeting or by submitting their proxies:

QEP stockholders who hold their shares in “street name” by a broker, bank or other nominee should refer to the proxy card, voting instruction form or other information forwarded by their broker, bank or other nominee for instructions on how to vote their shares.

Voting Virtually on the QEP Special Meeting Website

Shares held directly in your name as stockholder of record may be voted virtually on the QEP special meeting website at the QEP special meeting. If you choose to vote your shares at the QEP special meeting, you will need proof of identification. Even if you plan to attend the QEP special meeting, the QEP board recommends that you vote your shares in advance as described below so that your vote will be counted if you later decide not to attend the QEP special meeting.

If you are a beneficial holder, you will receive separate voting instructions from your broker, bank or other nominee explaining how to vote your shares. Please note that if your shares are held in “street name” by a broker, bank or other nominee and you wish to vote at the QEP special meeting to be held virtually on the QEP special meeting website, you will not be permitted to vote at the QEP special meeting unless you first obtain a legal proxy issued in your name from the record owner. You are encouraged to request a legal proxy from your broker, bank or other nominee promptly as the process can be lengthy.

Voting by Proxy

Whether you hold your shares of QEP common stock directly as the stockholder of record or beneficially in “street name,” you may direct your vote by proxy without attending the QEP special meeting. You can vote by proxy by phone, the Internet or mail by following the instructions provided in the enclosed proxy card.

Questions About Voting

If you have any questions about how to vote or direct a vote in respect of your shares of QEP common stock, you may contact Georgeson LLC, QEP’s proxy solicitor, at (800) 903-2897 (toll-free in North America).

Revocability of Proxies

If you are a stockholder of record of QEP, whether you vote by phone, the Internet or mail, you can change or revoke your proxy before it is voted at the meeting in one of the following ways:

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Proxy Solicitation Costs

The enclosed proxy card is being solicited on behalf of the QEP board. In addition to solicitation by mail, QEP’s directors, officers and employees may solicit proxies in person, by phone or by electronic means. These persons will not be specifically compensated for conducting such solicitation.

QEP has retained Georgeson LLC to assist in the solicitation process. QEP estimates it will pay Georgeson LLC a base fee of approximately $15,000, in addition to the reimbursement of certain costs and expenses, for these services. QEP also has agreed to indemnify Georgeson LLC against various liabilities and expenses that relate to or arise out of its solicitation of proxies (subject to certain exceptions).

QEP will ask brokers, banks and other nominees to forward the proxy solicitation materials to the beneficial owners of shares of QEP common stock held of record by such nominee holders. QEP will reimburse these nominee holders for their customary clerical and mailing expenses incurred in forwarding the proxy solicitation materials to the beneficial owners.

Adjournment

Whether or not a quorum is present, the holders of a majority of the outstanding shares of QEP common stock who are present in person or by proxy and entitled to vote at the special meeting may adjourn the meeting from time to time, without notice other than by announcement at the meeting, to another date, place, if any, and time until a quorum is present. Even if a quorum is present, the special meeting may also be adjourned in order to provide more time to solicit additional proxies in favor of adoption of the merger agreement if sufficient votes are cast in favor of the adjournment proposal. If the adjournment is for more than 30 days or if after the adjournment, a new record date is fixed for the adjourned meeting, QEP will provide a notice of the adjourned meeting to each stockholder of record entitled to vote at the meeting.

QEP’s bylaws also provide that the person presiding over any meeting of stockholders shall have the right and authority to convene and (for any or no reason) to recess and/or adjourn the meeting, to prescribe such rules, regulations and procedures and to do all such acts as, in the judgment of such presiding person, are appropriate for the proper conduct of the meeting. The presiding person at any meeting of stockholders, in addition to making any other determinations that may be appropriate to the conduct of the meeting, shall, if the facts warrant, determine and declare to the meeting that a matter or business was not properly brought before the meeting and if such presiding person should so determine, such presiding person shall so declare to the meeting and any such matter or business not properly brought before the meeting shall not be transacted or considered.

In addition, the merger agreement provides that QEP (i) will be required to adjourn or postpone the QEP special meeting to the extent necessary to ensure that any legally required supplement or amendment to this proxy statement/prospectus is provided to the QEP stockholders or if, as of the time the QEP special meeting is scheduled, there are insufficient shares of QEP common stock represented to constitute a quorum necessary to conduct business at the QEP special meeting, and (ii) may adjourn or postpone the QEP special meeting after consultation in good faith with Diamondback, if, as of the time for which the QEP special meeting is scheduled, QEP reasonably determines in good faith that there are insufficient shares of QEP common stock represented to obtain the approval of the merger proposal. However, unless Diamondback and QEP otherwise agree, the QEP special meeting will not be adjourned or postponed to a date that is more than ten business days after the date for

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which the QEP special meeting was previously scheduled (though the QEP special meeting may only be adjourned or postponed without Diamondback’s written consent once in the event that the circumstances described in (i) exist, and may be adjourned or postponed every time the circumstances described in (ii) exist) or to a date on or after two business days prior to the end date or if such adjournment or postponement would require the setting of a new QEP record date (as defined under “The Merger Agreement—Termination—Termination Rights”).

If a sufficient number of shares of QEP common stock is present in person or represented by proxy and vote in favor of the merger proposal at the special meeting such that the merger proposal is approved, QEP does not anticipate that it will adjourn or postpone the special meeting. Virtual attendance at the special meeting will constitute presence in person for the purpose of determining the presence of a quorum for the transaction of business at the special meeting.

No Appraisal Rights in the Merger

Under Delaware law, QEP stockholders are not entitled to appraisal rights in connection with the merger. For more information, see “The Merger—No Appraisal Rights in the Merger.”

Other Information

The matters to be considered at the QEP special meeting are of great importance to the QEP stockholders. Accordingly, you are urged to read and carefully consider the information contained in or incorporated by reference into this proxy statement/prospectus and submit your proxy by phone or the Internet or complete, date, sign and promptly return the enclosed proxy card in the enclosed postage-paid envelope. If you submit your proxy by phone or the Internet, you do not need to return the enclosed proxy card.

Assistance

If you need assistance in completing your proxy card or have questions regarding the QEP special meeting, contact:

Georgeson LLC

1290 Avenue of the Americas, 9^th Floor

New York, New York 10104

Stockholders, Banks and Brokers may call Toll-Free (North America): (800) 903-2897.

Vote of QEP’s Directors and Executive Officers

As of the close of business on January 21, 2021, the latest practicable date prior to the date of this proxy statement/prospectus, QEP directors and executive officers, and their affiliates, as a group, owned and were entitled to vote 2,348,050 shares of QEP common stock, or approximately 0.97% of the total outstanding shares of QEP common stock outstanding on that date. For more information regarding the security ownership of QEP directors and executive officers, please see “Share Ownership of Directors, Executive Officers and Certain Beneficial Owners of QEP—QEP’s Directors and Executive Officers” beginning on page 172.

QEP currently expects that all of its directors and executive officers will vote their shares “FOR” the merger proposal, “FOR” the non-binding compensation advisory proposal and “FOR” the approval of the adjournment proposal.

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Attending the QEP Special Meeting Virtually on the QEP Special Meeting Website

You are entitled to attend the QEP special meeting only if you were a stockholder of record of QEP at the close of business on the QEP record date or you held your shares of QEP beneficially in the name of a broker, bank or other nominee as of the QEP record date, or you hold a valid proxy for the QEP special meeting.

If you were a stockholder of record of QEP at the close of business on the QEP record date and wish to attend the QEP special meeting virtually on the QEP special meeting website, you should be prepared to present government-issued photo identification for admittance. If you do not provide photo identification or comply with the other procedures outlined above upon request, you might not be admitted to the QEP special meeting.

If a broker, bank or other nominee is the record owner of your shares of QEP common stock, you will need to have proof that you are the beneficial owner as of the QEP record date to be admitted to the QEP special meeting. A recent statement or letter from your broker, bank or other nominee confirming your ownership as of the QEP record date, or presentation of a valid proxy from a broker, bank or other nominee that is the record owner of your shares, would be acceptable proof of your beneficial ownership.

Results of the QEP Special Meeting

Within four business days following the QEP special meeting, QEP intends to file the final voting results with the SEC on a Current Report on Form 8-K. If the final voting results have not been certified within that four business day period, QEP will report the preliminary voting results on a Current Report on Form 8-K at that time and will file an amendment to the Current Report on Form 8-K to report the final voting results within four days of the date that the final results are certified.

QEP STOCKHOLDERS SHOULD CAREFULLY READ THIS PROXY STATEMENT/PROSPECTUS IN ITS ENTIRETY FOR MORE DETAILED INFORMATION CONCERNING THE MERGER PROPOSAL, THE NON-BINDING COMPENSATION ADVISORY PROPOSAL AND THE ADJOURNMENT PROPOSAL.

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QEP STOCKHOLDER PROPOSALS

Merger Proposal

In the merger proposal, QEP is asking its stockholders to adopt the merger agreement.

It is a condition to completion of the merger that QEP stockholders approve the merger proposal. As a result of the merger, each eligible share of QEP common stock (other than (i) shares held in treasury by QEP, (ii) shares owned by Diamondback or Merger Sub and, in each case, not held on behalf of third parties (the shares referred to in clauses (i) and (ii) collectively, the “cancelled shares”) and (iii) certain shares of QEP common stock subject to stock-based awards that will be treated in the manner described in the section entitled “The Merger Agreement—Treatment of QEP Equity Awards in the Merger” beginning on page 113) issued and outstanding immediately prior to the effective time of the merger will be converted into the right to receive 0.050 of a share of Diamondback common stock, with cash being paid in lieu of any fractional shares (the “merger consideration”), subject to certain exceptions as further described in the sections entitled “The Merger—Consideration to QEP Stockholders,” “The Merger Agreement—Effect of the Merger on Capital Stock; Merger Consideration” and “The Merger—No Appraisal Rights in the Merger” beginning on pages 60, 112 and 108, respectively.

The approval by the QEP stockholders of this proposal is required by the DGCL and is a condition to the consummation of the merger.

Approval of the merger proposal requires the affirmative vote of a majority of the outstanding shares of QEP common stock entitled to vote on the proposal. Abstentions and broker non-votes will have the same effect as a vote “AGAINST” the merger proposal. Failure to vote on the merger proposal will have the same effect as a vote “AGAINST” the merger proposal.

The QEP board unanimously recommends a vote “FOR” the merger proposal.

Non-Binding Compensation Advisory Proposal

QEP is also asking its stockholders to approve the non-binding compensation advisory proposal.

As required by Section 14A of the Exchange Act and the applicable SEC rules issued thereunder, which were enacted pursuant to the Dodd-Frank Wall Street Reform and Consumer Protection Act, QEP is required to provide its stockholders the opportunity to vote to approve, on a non-binding, advisory basis, certain compensation that may be paid or become payable to QEP’s named executive officers that is based on or otherwise relates to the merger, as described in the section entitled “The Merger—Interests of QEP’s Directors and Executive Officers in the Merger—Quantification of Potential Payments to QEP’s Named Executive Officers in Connection with the Merger” beginning on page 106. Accordingly, QEP stockholders are being provided the opportunity to cast an advisory vote on such payments.

As an advisory vote, this proposal is not binding upon QEP or the QEP board or Diamondback or the Diamondback board, and approval of this proposal is not a condition to completion of the merger and is a vote separate and apart from the merger proposal. Accordingly, you may vote to approve the merger proposal and vote not to approve the non-binding compensation advisory proposal and vice versa. Because the executive compensation to be paid in connection with the merger is based on the terms of the merger agreement as well as the contractual arrangements with QEP’s named executive officers, such compensation will be payable, regardless of the outcome of this advisory vote, only if the merger proposal is approved (subject only to the contractual conditions applicable thereto). However, QEP seeks the support of its stockholders and believes that stockholder support is appropriate because QEP has a comprehensive executive compensation program designed

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to link the compensation of its executives with QEP’s performance and the interests of QEP stockholders. Accordingly, holders of shares of QEP common stock are being asked to vote on the following resolution:

RESOLVED, that the stockholders of QEP Resources, Inc. approve, on an advisory, non-binding basis, certain compensation that may be paid or become payable to the named executive officers of QEP Resources, Inc. that is based on or otherwise relates to the merger, as disclosed pursuant to Item 402(t) of Regulation S-K under the heading “The Merger—Interests of QEP’s Directors and Executive Officers in the Merger—Quantification of Potential Payments to QEP’s Named Executive Officers in Connection with the Merger,” in the proxy statement/prospectus of QEP Resources, Inc. with respect to the special meeting of stockholders to be held on March 16, 2021.

Approval of the non-binding compensation advisory proposal requires the affirmative vote of a majority of the shares of QEP common stock present in person or represented by proxy at the QEP special meeting and entitled to vote on the proposal. Abstentions will have the same effect as a vote “AGAINST” the proposal, and broker non-votes will have no effect on the outcome of the vote.

The QEP board unanimously recommends a vote “FOR” the non-binding compensation advisory proposal.

The Adjournment Proposal

In the adjournment proposal, QEP is asking its stockholders to approve the adjournment of the special meeting, if necessary or appropriate, to solicit additional proxies if there are not sufficient votes to adopt the merger agreement.

If QEP stockholders approve the adjournment proposal, subject to the terms of the merger agreement, QEP could adjourn the special meeting and use the additional time to solicit additional proxies, including soliciting proxies from QEP stockholders who have previously voted. QEP does not intend to call a vote on the adjournment proposal if the merger proposal is approved at the special meeting.

Approval of the adjournment proposal requires the affirmative vote of a majority of the shares of QEP common stock present in person or represented by proxy at the QEP special meeting and entitled to vote on the proposal. Abstentions will have the same effect as a vote “AGAINST” the proposal, and broker non-votes will have no effect on the outcome of the vote.

The QEP board unanimously recommends a vote “FOR” the adjournment proposal.

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THE MERGER

This discussion of the merger is qualified in its entirety by reference to the merger agreement, which is attached to this proxy statement/prospectus as Annex A and incorporated by reference herein in its entirety. You should read the entire merger agreement carefully as it is the legal document that governs the merger.

Transaction Structure

At the effective time of the merger, Merger Sub will merge with and into QEP. As a result of the merger, the separate corporate existence of Merger Sub will cease, and QEP will continue as the surviving corporation in the merger and as a wholly owned subsidiary of Diamondback.

Consideration to QEP Stockholders

As a result of the merger, each eligible share of QEP common stock (other than any cancelled shares) issued and outstanding immediately prior to the effective time of the merger will be converted into the right to receive the merger consideration.

QEP stockholders will not be entitled to receive any fractional shares of Diamondback common stock in the merger, and no QEP stockholders will be entitled to receive dividends, voting rights or any other rights in respect of any fractional shares of Diamondback common stock. QEP stockholders that would have otherwise been entitled to receive a fractional share of Diamondback common stock will instead be entitled to receive, in lieu of fractional shares, an amount in cash, without interest, equal to the product of the volume weighted average price of Diamondback common stock for the five consecutive trading days ending on the date that is two trading days prior to the closing date, as reported by Bloomberg, L.P., multiplied by the fraction of a share of Diamondback common stock to which the holder would otherwise be entitled.

Background of the Merger

The QEP board and management, in the ordinary course continually evaluate QEP’s operations with a focus on creating long-term value by leveraging assets to create efficiencies, generating free cash flow and returning capital to stockholders. In connection with such evaluation, the QEP board and management also review and assess potential strategic alternatives available to QEP, including mergers and acquisition transactions and liability management. As part of such assessment, QEP management has contacts from time to time with financial and strategic parties, including other public and private exploration and production (“E&P”) companies.

The Diamondback board and Diamondback management periodically review opportunities to acquire assets or companies in the oil and gas industry that meet its strategic and financial objectives. As part of such reviews, Diamondback management has contacts from time to time with financial and strategic parties, including other public and private E&P companies.

In connection with its previously announced strategy to divest assets in order to become a pure play Permian company, QEP entered into agreements in the second half of 2018 to divest its Williston Basin assets, Louisiana natural gas assets and Uinta Basin assets.

On January 7, 2019, hedge fund Elliott Management Corp. (“Elliott”) made a conditional offer to buy QEP for $8.75 per share. In response to the public offer, QEP engaged Latham & Watkins LLP (“Latham”) and Evercore Group L.L.C. (“Evercore”) as its legal and financial advisors, respectively. The QEP board also engaged Wachtell Lipton Rosen & Katz (“Wachtell”) to advise the board with respect to Elliott and shareholder activism matters.

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On January 7, 2019, the QEP board held a telephonic meeting to discuss Elliott’s offer. Representatives of Latham provided the board with an overview of its fiduciary duties under Delaware law and risks associated with transactions similar to the one contemplated by Elliott’s offer. After discussing the offer, the QEP board instructed management to respond to Elliott that the QEP board was evaluating the offer. On the same day, QEP publicly announced that it had received the conditional offer from Elliott and that the QEP board was evaluating the offer.

On January 10, 2019, QEP announced that it closed the sale of its Louisiana natural gas assets to Aethon Energy for $735.0 million, subject to customary purchase price adjustments.

On January 17, 2019, the QEP board held a telephonic meeting to discuss, among other things, the status of the Williston and Louisiana divestitures and Elliott’s offer. The board was informed that the Louisiana asset divestiture had closed and that QEP management had been approached by Vantage Acquisition Operating Company LLC (“Vantage”), the proposed buyer of the Williston assets, to discuss the transaction and market conditions. Representatives of Evercore then provided the board with an overview of market conditions and a summary of unsolicited calls received from parties potentially interested in a strategic transaction with QEP. Representatives of Evercore informed the board that Evercore would be in a position to provide its preliminary financial analysis of the Elliott offer at the January 24, 2019 board meeting. The board then discussed whether initiating a sales process would be in the best interest of QEP and its stockholders, and the board determined to continue the discussion at the January 24, 2019 meeting. Representatives of Wachtell then reminded the board of its fiduciary duties in connection with a sales process.

On January 24, 2019, the QEP board held an in-person meeting to discuss Elliott’s offer and to discuss the potential market interest for and valuation of QEP. Representatives from Wachtell reminded the board of its fiduciary duties in response to Elliott’s offer. Representatives of Evercore provided the QEP board with Evercore’s preliminary financial analysis of Elliott’s offer. The QEP board determined that it was not going to engage in negotiations with Elliott at that time based on current data and the proposed offer price. The QEP board discussed whether to initiate a sales process and determined to continue the discussion at its regularly scheduled meetings on February 11, 2019 and February 12, 2019. In advance of those meetings, the QEP board instructed QEP management and Evercore to identify parties who might consider a strategic transaction with QEP and provide further information regarding QEP’s value in the market.

On January 30, 2019, the QEP board held a telephonic meeting to discuss materials prepared by Evercore regarding a potential sales process. Representatives of Evercore provided a general overview of the anticipated process. The QEP board determined to continue the discussion whether to initiate a sales process at its regularly scheduled meetings on February 11, 2019 and February 12, 2019.

On February 11, 2019, the QEP board held an in-person meeting to discuss, among other things, whether to initiate a comprehensive sales process. Representatives of Evercore provided the QEP board with an overview of the market and its preliminary financial analysis of the Elliott proposal. The QEP board discussed the merits of initiating a formal corporate-level sales process and noted that investors have increasingly favored companies with large market capitalizations that have the ability to maintain strong balance sheets across commodity price cycles, generate free cash flow and return capital to stockholders, either in the form of dividends or share repurchases. Representatives of Wachtell then reminded the board of its fiduciary duties in connection with a sales process. Upon concluding its discussion, the QEP board unanimously approved initiating a process to solicit third-party interest in a strategic transaction with QEP and instructed QEP management and Evercore accordingly.

On February 12, 2019, at the direction of the QEP board, representatives of Evercore began contacting representatives of potential acquirers and ultimately contacted representatives of 38 companies, including Diamondback.

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On February 20, 2019, QEP publicly announced that it had commenced a comprehensive review of strategic alternatives to maximize shareholder value, and disclosed that such process could result in the merger or sale of QEP. QEP announced that it intended to engage in discussions with a variety of parties that expressed interest in a potential transaction, including Elliott. QEP also announced that due to the deterioration in commodity prices and the unlikelihood that the conditions to closing would be satisfied, QEP and Vantage mutually agreed to terminate the agreement to sell QEP’s Williston Basin assets to Vantage.

From February 12, 2019 through April 10, 2019, QEP executed confidentiality agreements with 14 of the companies contacted by representatives of Evercore, including a confidentiality agreement with Diamondback executed on February 21, 2019. QEP and Evercore engaged in discussions with those parties that entered into confidentiality agreements and provided them with limited confidential information related to QEP’s assets and operations.

On April 10, 2019, QEP received three written proposals from Company A, Company B and Company C. Each proposal contemplated the acquisition of QEP via merger, with two proposals contemplating a stock-for-stock merger and a third proposal contemplating all cash consideration. The proposals ranged from a per share consideration amount of $7.55 per share to $8.75 share. Diamondback did not submit a proposal at that time.

On April 17, 2019, the QEP board held a meeting to discuss the three written proposals. Representatives of Evercore made a presentation to the QEP board, which included an overview of market conditions, a summary of the proposals and a summary of discussions with other potential counterparties that signed confidentiality agreements but elected to not submit proposals. At the end of the meeting, the QEP board authorized Evercore to invite Company A, Company B and Company C to participate in the next round of the process. The QEP board also instructed QEP management and Evercore to continue discussions regarding alternative structures, including asset sales, with a subset of the group of the 38 entities that had previously entered into confidentiality agreements.

Subsequent to the QEP board meeting on April 17, 2019, QEP and representatives of Evercore continued to discuss a potential transaction with each of Company A, Company B and Company C and shared additional information regarding QEP. QEP also conducted reverse due diligence with respect to Company A and Company C, the bidders that proposed stock-for-stock mergers.

On May 13, 2019, the QEP board held an in-person meeting. QEP management provided an overview of a standalone business plan and related analysis. Representatives of Evercore also gave an overview of market conditions, a preliminary financial analysis of QEP management’s standalone business plan and a preliminary financial analysis with respect to a potential combination with Company A and Company C.

On June 7, 2019, Company B submitted a bid to acquire QEP’s stock for consideration ranging from $6.50 to $7.00 per share. Company B’s proposal did not conform to the required second round bid parameters that representatives of Evercore communicated to bidders, because it did not include committed financing and indirectly conditioned the transaction on, among other things, the sale of QEP’s Williston Basin assets.

On June 11, 2019, the QEP board held an in-person meeting to discuss the results of the round two process, which consisted solely of a non-conforming bid from Company B. Company C indicated that it had continued interest in a combination, but was not willing to submit a proposal due to market conditions. Representatives of Evercore provided the board with a preliminary financial analysis of Company B’s proposal and an updated preliminary financial analysis of QEP management’s standalone business plan. QEP management also presented the QEP board with its analysis of moving forward as a standalone business. At the end of the meeting, the QEP board invited representatives from Company C to join the meeting and present the QEP board with an overview of Company C and the structure of a potential transaction. The QEP board instructed management and Evercore to continue discussions with Company B and Company C.

On July 7, 2019 and July 9, 2019, Company B and Company C submitted revised proposals with consideration of $6.75 per share and $5.18 per share, respectively. Company B’s proposal was non-conforming once again because it was not accompanied by binding commitment papers.

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On July 17, 2019, the QEP board held a telephonic meeting to evaluate and discuss the revised proposals. Representatives of Evercore provided the board with a market update and a preliminary financial analysis of Company B’s proposal. The board was also informed that due to recent developments at Company B, Company B would be submitting a revised proposal as soon as possible. The QEP board determined that Company C’s offer was not attractive relative to QEP’s proposed standalone business plan, and Evercore and QEP management were instructed to inform Company C that they were not interested in pursuing a transaction with Company C.

On July 25, 2019, Company B submitted a revised, non-conforming proposal and term sheet. The offer was conditioned on the sale of QEP’s Williston assets to Company B, the issuance and sale by QEP of $500 million of a preferred security to Company B and a cash tender offer by QEP at $7.00 per share with a cap of approximately $1.0 billion. Company B’s offer provided that QEP would fund the tender offer with the proceeds from the sale of the Williston assets and the preferred equity. Timothy J. Cutt, QEP’s President and Chief Executive Officer, and David Trice, then QEP’s Chairman, had a conversation with representatives of Company B to discuss the proposal.

On July 30, 2019, the QEP board met telephonically to discuss Company B’s revised proposal. Representatives of Evercore provided the QEP board with a preliminary financial analysis of Company B’s revised proposal. The QEP board discussed the proposal as well as QEP management’s proposed standalone case. After taking into account market conditions and the terms of Company B’s proposal, including closing conditions and risk of execution, the QEP board determined that it was in the best interests of QEP’s stockholders to continue as an independent company.

From July 30, 2019 through August 6, 2019, QEP and Elliott negotiated the terms of a cooperation agreement. On August 6, 2019, QEP and Elliott entered into the cooperation agreement, which provided, among other things, that QEP and Elliott would work together to identify and appoint two new independent directors to the QEP board. QEP also agreed to create a new five-person operations committee of the QEP board, which would include the new directors, and would focus on identifying best practices in the areas of QEP’s operations and on continuous improvement and excellence, with the objective to achieve leading levels of capital efficiency.

On August 7, 2019, QEP announced it had concluded its strategic review process and determined that the best path to create superior value for its stockholders was to move forward as an independent company. QEP also announced the entry into the cooperation agreement with Elliott.

From August 2019 onward, QEP management focused on executing its standalone business plan.

On December 12, 2019, representatives of Private Equity Sponsor A contacted QEP to discuss a potential transaction with Company D, a portfolio company of Private Equity Sponsor A. Private Equity Sponsor A provided information with respect to Company D to QEP without entering into a confidentiality agreement.

On December 22, 2019, QEP received an indication of interest from Company E, proposing a stock-for-stock merger and a concurrent equity infusion to the combined company from a third-party financing source. Representatives of Evercore provided a preliminary financial analysis of the proposed transaction to the QEP board on December 24, 2019.

On December 27, 2019, the QEP board reviewed Company E’s proposal as well as Evercore’s preliminary financial analysis of Company E’s proposal. The QEP board determined that it was not interested in pursuing a deal with Company E, primarily due to the lack of strategic overlap of the respective company’s assets, and instructed QEP management and representatives of Evercore to inform Company E.

On January 10, 2020, Company E’s chief executive officer had a telephone call with Mr. Cutt, and Mr. Cutt confirmed that QEP was not presently interested in pursuing a transaction with Company E.

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On January 17, 2020, William J. Buese, QEP’s Vice President, Chief Executive Officer and Treasurer, and representatives of Private Equity Sponsor B exchanged e-mail correspondence regarding a potential transaction involving QEP and one or more portfolio companies of Private Equity Sponsor B. The parties agreed to schedule a meeting to further discuss a proposed transaction.

On January 27, 2020, QEP management and representatives of Private Equity Sponsor B met to discuss a potential transaction involving Company F, a portfolio company of Private Equity Sponsor B.

On January 27, 2020, QEP management and representatives of Company F discussed entering into a confidentiality agreement to evaluate a potential transaction, and on February 5, 2020, the parties executed a confidentiality agreement.

In early 2020, Diamondback’s business development team began reviewing publicly available information regarding QEP in connection with again considering a potential transaction.

On February 14, 2020, the Diamondback board met telephonically and received an update from Diamondback’s management on their views regarding a potential transaction with QEP. After discussion, the Diamondback board authorized management to continue its investigation of a potential transaction with QEP and to contact QEP management. However, Diamondback management was unable to contact QEP prior to the onset of the coronavirus pandemic in the U.S., and so determined to put outreach to QEP on hold.

On February 19, 2020, the QEP board held a regularly scheduled in-person meeting to discuss, among other things, QEP’s 2020 business plan and potential strategic transactions, including (i) a sale or joint venture of QEP’s Permian water business, (ii) the disposition of QEP’s Williston Basin assets, (iii) a potential transaction with Private Equity Sponsor A and Company D and (iv) a potential transaction with Private Equity Sponsor B and Company F. Representatives of BMO Capital Markets (“BMO”), which had previously been engaged by QEP in connection with the proposed sale of QEP’s Williston assets to Vantage, provided an overview of the proposed terms for a transaction involving QEP’s Permian water business, an overview of the marketing process and a summary of proposals received from potential counterparties. Representatives of BMO then provided the board with an updated financial analysis of the Williston Basin assets and an analysis of precedent Williston Basin transactions. Representatives of Evercore then provided the board with a market overview and an updated preliminary financial analysis regarding a potential transaction with Company D or Company F and other strategic alternatives.

From February 19, 2020 through March 18, 2020, QEP management continued to exchange correspondence and have discussions with representatives of Private Equity Sponsor B regarding a potential transaction with Company F, and on February 20, 2020 QEP and Private Equity Sponsor B entered into a confidentiality agreement.

The QEP board noted investors’ focus on scale, strong balance sheets and the ability of issuers to return capital to stockholders was further accelerated and heightened in March 2020, when the global response to COVID-19. The QEP board believed that together with periods of increased production from foreign oil producers (most notably Saudi Arabia and Russia), this resulted in steep declines in the prices of oil and NGL and severe temporary storage shortages, negatively impacting oil and gas producers located in the United States, including QEP.

On March 12, 2020, in response to these events and an increased focus on risk management strategies, the QEP board held a telephonic meeting to discuss QEP management’s recommendations regarding a revised operating plan for the balance of 2020 and liability management options with respect to QEP’s balance sheet. The QEP board unanimously approved a number of operational adjustments recommended by management to enhance QEP’s ability to generate cash flow and avoid incurring additional leverage.

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On March 13, 2020, QEP issued a press release announcing, among other things, an approximate 30% reduction in its capital budget, a plan to suspend completion operations in the Permian Basin from May 2020 until at least the beginning of the fourth quarter 2020, the release of an intermediate drilling rig in the Permian Basin and a suspension of its quarterly dividend.

On March 25, 2020, Mr. Cutt had a telephone call with representatives of Private Equity Sponsor A regarding a potential transaction with Company D.

On March 30, 2020, the QEP board held a telephonic board meeting to discuss QEP’s response to market conditions and discuss QEP’s capital structure and options to strengthen its balance sheet through liability management transactions. In response to a continuing decline in commodity prices due to increased global production as well as heightened concerns over COVID-19 and its impact on the global demand for oil, QEP management recommended dropping an additional rig and continuing to drill with one rig, suspending fracking operations in the Permian through at least November 1, 2020 (pending commodity price improvement) and deferring drilling one salt water disposal well. These actions would be in addition to those previously announced on March 13, 2020. QEP management advised the board that these actions were designed to improve cash flow and preserve liquidity and would result in further reductions of QEP’s original 2020 capital expenditures budget. QEP management also provided the board with an overview of QEP’s capital structure and liquidity position and recommendations for addressing its upcoming revolver and bond maturities in 2022 and 2023 given the distressed commodity price environment. Mr. Buese then provided the board with an update on liability management and the status of QEP’s discussions with its bank group and various options QEP could pursue to secure additional liquidity, noting the restrictions on incurring secured debt in QEP’s existing indentures governing its senior notes. Mr. Buese also provided the board with an update on the trading activity of QEP’s outstanding senior notes. The board, QEP management and representatives of Evercore engaged in further discussions regarding QEP’s capital structure and available options to address liquidity and near-term maturities.

From March 31, 2020 through May 1, 2020, QEP management, representatives of Private Equity Sponsor A and representatives of Evercore continued to have discussions regarding a potential transaction with Company D, and the benefits to each party due to the complementary nature of each party’s assets.

On April 16, 2020, the QEP board held a telephonic board meeting to discuss with QEP management the ongoing pandemic and market disruptions, as well as QEP’s responsive actions to date, and QEP’s performance, strategy, financial position and opportunities in the current market environment, including the exploration of opportunities to combine with a potential merger partner to achieve benefits of scale and efficiency. In addition, the QEP board and QEP management discussed other options that could be available to refinance indebtedness through conventional and alternative financing transactions and raise additional capital through asset sales or other asset monetizations. As part of this discussion, the QEP board discussed its perspective on strategic objectives and key investment metrics that were likely to enhance investor interest in the industry in general and QEP in particular. Mr. Cutt then provided the board with a status update on discussions with Private Equity Sponsor A/Company D and Private Equity Sponsor B/Company F. Mr. Buese provided the board with an update on QEP’s negotiations with its lender group regarding a potential amendment to QEP’s existing credit facility.

The QEP board noted at its meeting on April 16, 2020 that QEP management’s actions in response to the oil price war and COVID-19 had positioned QEP to withstand an extended downturn and generate free cash flow despite challenging market conditions, but acknowledged that significant downside risk remained. The QEP board discussed with QEP management the potential benefits and drawbacks of pursuing a strategic combination, including the potential benefits to QEP’s stockholders if QEP were to combine in an all-stock transaction to form a company with a lower cost of capital, lower leverage and larger market capitalization than QEP on a standalone basis. The QEP board requested that QEP management continue to evaluate the possibility of a strategic combination and continue discussions with Private Equity Sponsor A and Private Equity Sponsor B. In addition, the QEP board requested that QEP management evaluate the potential benefits of alternative financing transactions, including liability management and the monetization of QEP’s water assets.

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On May 6, 2020, QEP, Private Equity Sponsor A and Company D entered into a confidentiality agreement with respect to a potential transaction involving QEP and Company D. From May 7, 2020 through July 13, 2020, QEP and Company D continued to exchange data and perform technical diligence on each party’s assets.

On June 4, 2020, QEP announced that it amended its credit facility, increasing its liquidity by more than $500 million and providing additional financial flexibility to help execute its ongoing business plan.

On June 5, 2020, Mr. Cutt and representatives of Private Equity Sponsor B exchanged correspondence to revisit a potential transaction involving Company F as well as Company G, a second portfolio company of Private Equity Sponsor B with assets located in the Permian Basin. The parties agreed to continue discussions involving a potential transaction, and Private Equity Sponsor B committed to provide QEP with additional materials regarding Company F and Company G.

On June 12, 2020, representatives of Company H contacted Mr. Cutt to discuss a potential business combination with QEP. Mr. Cutt expressed a willingness to discuss a proposed transaction, and Company H sent Mr. Cutt an indication of interest as well as a presentation for QEP’s review and consideration.

On June 23, 2020, representatives of Evercore provided QEP management with its preliminary financial analysis of a proposed transaction with Company H. QEP management reviewed the Evercore materials and concluded that pursuing a transaction with Company H was not in the best interest of QEP and its stockholders and forwarded the proposal to the QEP board with a recommendation that QEP not pursue a transaction with Company H. The QEP board agreed with management’s recommendation and instructed Mr. Cutt to inform Company H of its decision.

On June 24, 2020, Mr. Cutt informed representatives of Company H that QEP was not interested in pursuing a transaction with Company H.

On July 2, 2020, representatives from Company I sent an email to Mr. Cutt expressing an interest in a potential transaction and asked for Mr. Cutt’s willingness to schedule a call to discuss a potential transaction. Mr. Cutt responded and a call was scheduled for July 21, 2020.

On July 7, 2020, Private Equity Sponsor B submitted an indication of interest to QEP regarding its proposed transaction with Company F and Company G.

On July 10, 2020, QEP management discussed with representatives of Private Equity Sponsor A a potential transaction where QEP would acquire all or substantially all of the equity or assets of Company D in exchange for QEP stock. From July 10, 2020 through July 21, 2020, QEP management, representatives of Private Equity Sponsor A and representatives of Evercore continued to have discussions regarding the proposed transaction after which QEP and Private Equity Sponsor A suspended discussions with respect to a proposed transaction involving Company D.

On July 15, 2020, QEP received access to a data room populated by Private Equity Sponsor B with information regarding Company F and Company G.

On July 21, 2020, Mr. Cutt and representatives from Company I held an introductory telephone call regarding a potential transaction. Company I’s management expressed its interest in moving into the Permian Basin and that Company I would be interested in discussing a possible combination with QEP. Mr. Cutt expressed an interest in discussing such a transaction.

On July 22, 2020, Mr. Cutt received a call from management of Company J. The parties discussed areas of mutual interest and Company J’s recent interest in acquiring certain acreage in QEP’s Williston position. Mr. Cutt informed Company J that QEP was not interested in only selling selective portions of QEP’s Williston

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acreage. Company J then conveyed that it may be interested in a corporate transaction as part of a strategy to enter the Midland Basin within the Permian Basin. Mr. Cutt and representatives of Company J acknowledged that each company was approaching earnings season and agreed to continue the discussion following their respective earnings releases.

On July 23, 2020, representatives from Company I reached out to Mr. Cutt telephonically and mentioned that Company I would like to send over a high-level combination analysis with respect to QEP and Company I. Mr. Cutt agreed to review the material, and Company I emailed an information deck to Mr. Cutt that afternoon.

On July 24, 2020, Christopher K. Woosley, QEP’s Executive Vice President, General Counsel and Corporate Secretary, had a telephone call with management of Company J, where they expressed Company J’s intent to be a consolidator in the Permian Basin. Company J’s management explained they held a strategy session with Company J’s board and identified QEP as one of several companies they were interested in and that Company J would like to enter into a confidentiality agreement with QEP in order to review an initial list of diligence items. Mr. Woosley gave Mr. Cutt a summary of the call. On July 27, 2020, Company J sent QEP a draft confidentiality agreement for its review.

On July 28, 2020, at a regularly scheduled videoconference meeting, the QEP board discussed, among other things, an update on liability management and strategic alternatives with Company D, Company F, Company G, Company I and Company J. Mr. Buese provided the board with an overview of (i) the recent amendment QEP entered into with respect to its credit facility, (ii) total senior notes outstanding and (iii) authorizations to repurchase outstanding senior notes, including a summary of repurchases made in the first half of 2020. Mr. Buese then gave an overview of the market for new issuances of senior notes and a summary of indicative terms for a new issuance of guaranteed senior notes.

Representatives of Evercore provided the board with an update regarding status of discussions with each of Company D, Company F, Company G, Company I and Company J and Evercore’s preliminary financial analysis of each. Representatives of Evercore also provided a status update regarding the diligence process with respect to Company F and Company G. QEP management and representatives of Evercore noted that discussions with Private Equity Sponsor A were at an impasse regarding valuation and a path forward to address the combined company’s capital structure through liability management.

The QEP board then discussed with its advisors and considered current market conditions, the current reality for energy companies considering the ongoing COVID-19 pandemic, that the energy sector had significantly trailed the general market recovery, that despite active equity and debt capital markets across other sectors the few energy companies that were able to access capital markets were primarily large-cap, investment grade entities, and that efforts by highly levered exploration and production companies to exchange outstanding debt had limited participation levels.

Following a discussion, the QEP board determined that it was not interested in pursuing a transaction with Company I, but authorized QEP management and Evercore to continue discussions with Private Equity Sponsor B and Company J.

On July 31, 2020, Mr. Cutt sent an email to representatives of Company I informing them that QEP management had reviewed the opportunity with the QEP board and that QEP was not interested in pursuing a transaction at that time as the proposal was not competitive with, and did not provide as complimentary of an asset base compared with, other alternatives that were currently under consideration.

On August 3, 2020, QEP and Company J executed a confidentiality agreement. Throughout August, Mr. Cutt and members of Company J’s management had several email and telephonic exchanges regarding a potential transaction, with Company J continuing to express interest in a potential combination. In late August,

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discussions between Company J and QEP terminated with Company J noting its evaluation of a corporate transaction was complicated by concerns about the pro forma leverage that would occur in a combination of the two companies.

On August 14, 2020, Mr. Cutt and representatives of Company E had a telephone call to revisit a potential transaction, and on August 21, 2020, QEP received materials from Company E regarding a potential transaction.

On August 25, 2020, QEP received discussion materials from Private Equity Sponsor B regarding a potential transaction involving Company F and Company G. The same day, QEP management, representatives of Evercore and representatives of Private Equity Sponsor B participated on a telephone call to discuss the materials provided and a potential combination involving all three entities, the strategic rationale, valuation, liability management with respect to QEP’s outstanding senior notes and next steps.

On August 27, 2020, Company E sent an email to Mr. Cutt following up on the materials previously provided on August 21, 2020 and sought to arrange a call.

On September 1, 2020, Mr. Cutt responded to Company E informing Company E that it was premature to discuss a potential transaction. Mr. Cutt and Company E had additional communications on September 8, 2020 and September 29, 2020 regarding a potential transaction.

On September 2, 2020 and September 3, 2020, QEP management, representatives of Evercore and Private Equity Sponsor B met to conduct reciprocal technical diligence on QEP’s, Company F’s and Company G’s assets.

On September 9, 2020, members of QEP management and representatives of Evercore, Latham and Private Equity Sponsor B held meetings to conduct reciprocal corporate and financial diligence.

On September 10, 2020, the QEP board held a videoconference meeting to receive an update on strategic alternatives. Mr. Cutt provided a brief introduction, and noted that, based on diligence completed to date, management believed a transaction involving QEP, Company F and Company G could be an attractive opportunity due to the location of the assets, the positive impact on QEP’s balance sheet and the ability to bring a respected, knowledgeable energy investor – Private Equity Sponsor B – into QEP’s share register. Representatives of Evercore provided a market overview and status update with respect to the discussions with each potential counterparty.

Representatives of Evercore then provided to the board an updated preliminary financial analysis with respect to a potential business combination involving Company F and Company G based on diligence done to date. The presentation noted that Private Equity Sponsor B would condition the consummation of the business combination on QEP successfully executing a liability management transaction to address the near-term maturities of its 2022 and 2023 senior notes. The QEP board then discussed with its advisors the benefits of a liability management transaction, which included materially de-leveraging the balance sheet, extending maturities beyond 2023 to provide a capital structure that allows investors to realize the equity thesis of the combined company and ensure the combined company has adequate liquidity and flexibility to access traditional bank capital by entering into a secured reserve-based revolver.

The QEP board authorized management and Evercore to continue discussions with Private Equity Sponsor B regarding a potential business combination involving Company F and Company G.

From September 10, 2020 through September 24, 2020, QEP management and representatives of Evercore continued to conduct financial and technical diligence on Company F and Company G and engage in conversations with representatives of Private Equity Sponsor B regarding a potential transaction.

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On September 24, 2020, QEP management and representatives of Evercore participated on a telephone call with representatives of Private Equity Sponsor B where QEP outlined its financial analysis and response to the discussion materials submitted by Private Equity Sponsor B on August 25, 2020.

On September 30, 2020, Mr. Cutt and representatives of Private Equity Sponsor B had a telephone call to discuss the status of QEP’s feedback and next steps.

In the fall of 2020 Diamondback began discussions with Moelis & Company LLC (“Moelis”) regarding its corporate development strategy. Those conversations continued over the succeeding months, and included a discussion of a potential transaction with QEP.

On October 5, 2020, the QEP board held a videoconference meeting to discuss the proposed transaction with Private Equity Sponsor B, Company F and Company G and status of other strategic alternatives, including a standalone liability management exercise. QEP management provided the board with an overview of its technical and financial diligence done to date on Company F and Company G, and noted that Company F’s assets were stronger and more complimentary to QEP’s asset base compared to Company G’s assets.

Representatives of Evercore provided the board with an updated preliminary financial analysis of the proposed transaction with Company F and Company G.

Following a call between Company E and Mr. Cutt, and at the request of QEP management, representatives of Evercore then provided a preliminary financial analysis with respect to a potential business combination with Company E. The QEP board authorized management and Evercore to continue discussions with Private Equity Sponsor B regarding a potential transaction, but noted that it was only interested in pursuing a transaction with Company F and not Company G. The QEP board also instructed management and Evercore that it was not interested in pursuing a transaction with Company E and that they should not pursue any further discussions.

Mr. Buese then provided the QEP board with an overview of a proposed standalone liability management transaction should QEP choose to continue as a standalone company and not pursue a strategic business combination or similar transaction. Mr. Buese discussed the maturity profile of QEP’s outstanding debt and gave an illustrative example of management’s plan to obtain a secured reserve-based loan (“RBL”) that would provide adequate liquidity.

On October 7, 2020, Mr. Cutt informed representatives of Private Equity Sponsor B that QEP was interested in continuing discussions regarding a potential transaction, but it was only interested in pursuing a transaction with Company F, not Company G. From October 7, 2020 through October 21, 2020, QEP management, representatives of Evercore and representatives of Private Equity Sponsor B continued to discuss a potential transaction.

On October 7, 2020, Mr. Cutt notified representatives of Company E via email that the QEP board appreciated Company E’s indication of interest in a transaction with QEP but it was not interested in pursuing a transaction with Company E.

On October 8, 2020, Mr. Cutt had a phone call with representatives of Company E to discuss his email from the previous day. Mr. Cutt reiterated his message that QEP was not interested in pursuing a transaction with Company E at that time.

On October 21, 2020, Private Equity Sponsor B submitted a written proposal regarding a transaction involving Company F. The proposal contemplated QEP acquiring Company F in an all-stock transaction plus Private Equity Sponsor B investing cash in exchange for additional QEP equity. The offer contemplated that Private Equity Sponsor B would hold 75% of the outstanding common stock of the combined company and QEP’s stockholders would retain a 25% stake. The offer was subject to corporate governance discussions and

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confirmatory diligence and the transaction would be conditioned on, among other things, the successful execution of a liability management transaction, the terms of which were to be agreed upon with QEP.

On October 27, 2020, the QEP board held a regularly scheduled meeting to discuss, among other things, Private Equity Sponsor B’s proposed offer that was received on October 21, 2020 and the terms of a standalone liability management transaction. Also in attendance were certain members of QEP management and representatives of Evercore and Latham.

Mr. Buese provided an update on QEP’s standalone liability management strategy and RBL facility. He provided an overview of the proposed terms of a potential exchange offer involving QEP’s 2022 and 2023 senior notes in exchange for a new series of senior notes with an extended maturity date. Next, Mr. Buese provided a summary of key RBL facility terms and focus areas. He noted that management was in discussions with the QEP’s lenders regarding the RBL facility process and proposed terms. Evercore then provided illustrative terms of an exchange offer and QEP’s liquidity projections based on various assumptions. After further discussion, the board authorized management to continue negotiating the terms of a RBL facility and approved management to pursue an exchange offer.

Representatives of Evercore then provided a preliminary financial analysis with respect to the proposed transaction with Private Equity Sponsor B and Company F. Latham then provided the QEP board with an overview of the required approvals needed and the related voting thresholds to approve the proposed transaction. Latham also provided the board with an overview of fiduciary duties under Delaware law that would be applicable in a transaction of this nature and the governance structure that would be applicable to QEP post-transaction. Latham also advised on certain shareholder protections QEP should request as part of the negotiation with Private Equity Sponsor B. After discussing the proposed transaction in executive session, the board determined it was in the best interest of QEP and its stockholders to terminate discussions with Private Equity Sponsor B and proceed with the proposed standalone liability management transaction.

On October 28, 2020, Mr. Cutt called representatives of Private Equity Sponsor B and informed them that the QEP board decided that it was in the best interest of QEP and its stockholders to not pursue a transaction with Private Equity Sponsor B and Company F at that time.

From October 9, 2020 through November 30, 2020, QEP and representatives of Evercore and Latham (i) negotiated a term sheet for a RBL facility with, and solicited commitments from, the administrative agent and the joint book-running lenders under QEP’s existing credit facility and (ii) developed the terms of an exchange offer and consent solicitation with respect to its 2022 and 2023 senior notes, including a description of notes that would govern the terms of the exchange notes (clause (ii) is collectively referred to as the “Exchange Offer Term Sheet”).

On November 3, 2020, management of Company C called Mr. Cutt to discuss a potential combination involving QEP and Company C. Mr. Cutt told Company C management that QEP would be willing to discuss a potential transaction.

In early November of 2020, Diamondback’s senior management again began internal discussions about a potential transaction with QEP.

On November 11, 2020, management of Company C called Mr. Cutt and informed him that they intended to send Mr. Cutt a presentation outlining the benefits for a business combination between Company C and QEP. On November 12, 2020, management of Company C sent the presentation to Mr. Cutt.

On November 13, 2020, Mr. Cutt sent an email to the QEP board describing the proposed transaction with Company C. Mr. Cutt also advised the board that management did not believe that a transaction with Company C would be consistent with QEP’s current strategy of focusing on the Permian Basin.

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On November 16, 2020, Mr. Cutt and representatives of Evercore had a telephone call to discuss the merits of a transaction with Company C. Following this meeting, QEP agreed to enter into a confidentiality agreement with Company C to allow QEP to conduct one-way diligence on Company C. The confidentiality agreement with Company C was executed on November 19, 2020. Following the review of the information QEP received from Company C and input from the QEP board, Mr. Cutt informed management of Company C that QEP was not interested in pursuing a transaction with Company C.

On November 25, 2020, Latham contacted counsel to an ad hoc group of QEP noteholders (the “Ad Hoc Group”) to discuss wall crossing the Ad Hoc Group in order to negotiate the terms of an exchange offer and consent solicitation.

On November 25, 2020, Travis D. Stice, Diamondback’s Chief Executive Officer, and M. Kaes Van’t Hof, Diamondback’s Chief Financial Officer and Executive Vice President of Business Development, had a teleconference call with Steven West, Chairman of the Diamondback board, regarding a potential transaction with QEP. Mr. West indicated he was generally supportive of investigating a potential transaction, further discussion with the full Diamondback board and preliminary outreach to QEP.

On November 30, 2020, Mr. Stice contacted Mr. Cutt to inform him that Diamondback would be interested in making an offer to acquire QEP. Mr. Cutt responded that management of QEP and the QEP board would be willing to consider an offer.

On December 1, 2020 and December 2, 2020, QEP entered into confidentiality agreements with certain members of the Ad Hoc Group and circulated the Exchange Offer Term Sheet to the Ad Hoc Group.

On December 2, 2020, certain news organizations reported rumors that QEP had been contacted about a potential takeover.

From December 3, 2020 through December 18, 2020, QEP management and representatives of Evercore, Latham and the Ad Hoc Group and its counsel participated in discussions and negotiated the proposed terms of the exchange offer and consent solicitation.

On December 3, 2020, at a meeting of the QEP board held via videoconference, with certain members of QEP management and representatives of Evercore in attendance, Mr. Cutt notified the QEP board of Diamondback’s interest in a potential business combination with QEP. The QEP board engaged in a detailed discussion regarding the strategic rationale for a combination with Diamondback. The QEP board acknowledged the benefits of combining with an investment grade company such as Diamondback, the pro forma company’s operational scale, lower cost of capital, high asset quality, and its ability to generate free cash flow and return capital to stockholders. The QEP board also discussed the pros and cons of continuing as a standalone company, including the risk of an extended downturn caused by COVID-19, ongoing industry consolidation and negative investor sentiment towards the sector, the combination of which might further erode QEP’s trading multiples in comparison to larger competitors. Based on this discussion, the QEP board generally agreed that Diamondback was a very attractive potential merger partner. The QEP board authorized Mr. Cutt to continue discussions with Diamondback. During the board meeting, Mr. Buese provided the board with an update regarding the status of QEP’s proposed RBL facility and the proposed exchange offer and consent solicitation.

On December 3, 2020, Mr. Cutt called Mr. Stice to inform him that the QEP board was interested in continuing discussions with Diamondback regarding a potential business combination.

On December 3, the Diamondback board held a videoconference meeting to discuss, among other things, a potential transaction with QEP. The board members and certain members of management discussed certain financial and operational matters related to the proposed transaction, and then potential process. Following that discussion, the Diamondback board authorized Diamondback management to finalize an offer letter and related

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materials for an all-stock, at-market transaction, and to pursue the transaction, including engaging in due diligence and discussions with ratings agencies. The board stressed to Diamondback management the importance of maintaining Diamondback’s investment grade rating.

On December 7, 2020, Mr. Stice provided to Mr. Cutt a presentation containing certain information regarding Diamondback and the proposed transaction. That presentation noted that Diamondback believed it was the right counterparty for QEP, with complementary assets, an investment grade balance sheet, a strong free cash flow model built to return capital to stockholders and the size and scale to attract investors. It also stated that the exchange ratio would reflect an “at-market” transaction and emphasized that the all-stock nature of the proposed combination would provide QEP stockholders the opportunity to participate in the upside of the combined company as macroeconomic conditions improved.

Messrs. Stice and Van’t Hof then followed up with a phone call to review that presentation, indicated to Mr. Cutt that Diamondback was prepared to make an offer to acquire QEP and outlined the general terms of the proposed transaction. Mr. Stice emphasized Diamondback’s sensitivity to equity market reaction to a transaction premium perceived to be excessive, which would be to the detriment of both companies. Diamondback management concluded the call noting they would follow up with a formal offer letter and a confidentiality agreement.

Later that day, Mr. Cutt received an offer letter from Diamondback. The letter did not provide an exchange ratio; rather it provided that Diamondback was offering to acquire QEP in an all-stock, at-market transaction with an exchange ratio to be agreed upon closer to the execution of a definitive agreement. The letter indicated that the proposal implied a material premium relative to QEP’s unaffected share price as of December 1, 2020 (i.e., the last trading day before market rumors of a potential transaction). Mr. Stice also provided a draft confidentiality agreement for QEP to review and execute and requested exclusivity. Mr. Cutt notified the QEP board of Diamondback’s offer and recommended that QEP enter into the confidentiality agreement with Diamondback and start exchanging information and diligence materials with Diamondback.

Around the same time period, Mr. Woosley reached out to representatives of Evercore and Latham regarding the offer received from Diamondback. Mr. Woosley also authorized Latham to engage Richards, Layton & Finger, PA (“RLF”) to act as special Delaware counsel to QEP in connection with the proposed transaction. Mr. Woosley and representatives of Latham reviewed the draft confidentiality agreement provided by Diamondback, and Mr. Woosley sent a revised draft of the same to Mr. Van’t Hof.

On December 8, 2020, Messrs. Woosley and Van’t Hof had a telephone conversation to discuss general terms of the offer, timing, due diligence and other matters relating to the potential transaction. Later that day, QEP and Diamondback entered into a confidentiality agreement and each party was granted access to an electronic data room prepared by the other party. The confidentiality agreement included a customary mutual “standstill” provision that would automatically terminate if, among other things, either party entered into a definitive merger agreement with another party. Diamondback and QEP did not agree to exclusivity at that time.

From December 9, 2020 through December 20, 2020, QEP conducted extensive due diligence of Diamondback and Diamondback conducted extensive due diligence of QEP. Mr. Van’t Hof and P. Matt Zmigrosky, Diamondback’s Executive Vice President and General Counsel, held a series of reciprocal due diligence discussions, primarily with Mr. Woosley, and Lauren Baer, QEP’s Vice President, Human Resources & Community Investments. Representatives of QEP’s advisors (Latham and Evercore) and Diamondback’s advisors (Goldman Sachs & Co. LLC (“Goldman”) and Diamondback’s legal counsel, Akin Gump Strauss Hauer & Feld LLP (“Akin Gump”)) also attended the meetings.

On December 10, 2020, the Diamondback board held a telephonic meeting focused primarily on the potential transaction with Guidon, but Messrs. Stice and Van’t Hof provided the board with an update on the status of the outreach to QEP.

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From December 10, 2020 through December 17, 2020, Diamondback management delivered presentations to and responded to follow-up inquiries from its ratings agencies (Standard & Poor’s and Fitch Ratings) regarding the potential transactions with QEP and Guidon and their potential impacts on Diamondback.

On December 12, 2020, QEP received a draft of the merger agreement from Diamondback. From December 12 through December 20, the parties and their respective legal advisors negotiated the terms of the merger agreement.

On December 14, 2020, the Diamondback board held a videoconference telephonic meeting, which was also attended by certain members of Diamondback’s management and representatives from Goldman. The board asked questions of Goldman and management regarding the potential QEP acquisition. After deliberation and discussions, the board authorized management to finalize a follow-up offer letter proposing an exchange ratio of 0.050 of a share of Diamondback common stock for each share of QEP common stock and again requesting exclusivity. The board further authorized continuing due diligence, ratings agency discussions and negotiation of definitive documents.

Following the Diamondback board meeting, later on December 14, 2020, Mr. Cutt received an offer letter from Diamondback, which letter included a proposed exchange ratio of 0.050 of a share of Diamondback common stock for each share of QEP common stock. The letter further indicated that the 0.050 exchange ratio represented a 1% premium to QEP’s closing price on that same day, a 10% premium to the ten-day average closing price and a 26% premium to the twenty-day average closing price.

From December 14, 2020 through December 20, 2020, Messrs. Cutt and Stice had multiple discussions regarding the terms of the potential transaction.

Also on December 14, 2020, representatives from Latham reviewed and discussed with QEP management key provisions of the merger agreement draft that had been provided by Diamondback on December 12, 2020, including (i) the fact that the merger agreement provided for a transaction structure that would generally result in a tax free transaction for QEP stockholders, (ii) the key conditions to closing of the merger, including receipt of QEP stockholder approval, and (iii) the deal protection provisions, including the non-solicitation and “force the vote” covenants and the proposed termination fee and expense reimbursement obligations of QEP, which were based on QEP’s enterprise value. QEP management provided Latham with direction as to how to respond on key terms of the merger agreement, and authorized Latham to prepare and distribute a revised draft of the merger agreement to Diamondback.

On December 15, 2020, Latham sent Akin Gump a revised draft of the merger agreement that included the following key terms: (i) a right for the QEP board to terminate the merger agreement to permit QEP to enter into a definitive agreement with respect to a superior proposal, (ii) a termination fee and expense reimbursement obligations calculated to represent a percentage of QEP’s equity value and (iii) additional restrictions on the ability of Diamondback to engage in certain transactions that would materially alter the nature of Diamondback between signing and closing without QEP’s consent, including certain transactions involving the issuance of equity, the incurrence of debt and the acquisition or divestiture of material assets.

On December 16, 2020, the QEP board held a videoconference with certain members of QEP management, and representatives of Evercore and Latham in attendance, to discuss the offer letter received from Diamondback. At the outset of the meeting, representatives of Latham reviewed with the members of the QEP board their fiduciary duties under Delaware law with respect to the evaluation of a potential strategic combination. In addition, representatives of Latham discussed legal considerations related to actual or potential conflicts that could arise in connection with the evaluation of a strategic transaction.

Following the discussion of fiduciary duties led by Latham, representatives of Evercore reviewed with the QEP board its preliminary financial analysis with respect to a possible combination of QEP and Diamondback. Representatives of Evercore also reviewed and discussed with members of the QEP board and management the

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continued underperformance of the upstream oil and gas sector relative to other market sectors and the challenges associated with market positioning and attracting investor interest. After further discussion, the QEP board asked the Latham and Evercore representatives to leave the meeting to allow the QEP board to continue its discussion in executive session. At the conclusion of the meeting, the QEP board determined that it should seek a higher exchange ratio from Diamondback, and authorized a formal response to Diamondback seeking an exchange ratio of 0.053.

Later that same day, Mr. Cutt called Mr. Stice to advise him of the outcome of the QEP board meeting, and to discuss the economic terms of a potential combination. Mr. Cutt advised Mr. Stice that the QEP board was prepared to move forward at an exchange ratio of 0.053. Mr. Stice declined to agree to the proposed exchange ratio, but said he would discuss with the Diamondback board.

On December 17, Messrs. Stice and Van’t Hof had a teleconference call with Mr. West to discuss the ongoing negotiations with QEP. Mr. West informed Diamondback management that he would not support an offer with an exchange ratio in excess of 0.050 and encouraged Mr. Stice to inform QEP and again request exclusivity through December 24, 2020. Following that call, by email communication, Mr. Stice informed Mr. Cutt that Diamondback declined QEP’s counter offer, renewed Diamondback’s offer of an exchange ratio of 0.050 and requested exclusivity through December 24, 2020.

On that same day, the QEP board, along with representatives from management, Evercore and Latham, held a telephonic board meeting to discuss Diamondback’s proposal, including the 0.050 exchange ratio. Evercore provided the board with an update of its preliminary financial analysis as well as supplementary financial data that the QEP board requested during the December 16, 2020 meeting. The QEP board also discussed with management, representatives of Latham and representatives of Evercore, Diamondback’s request for exclusivity. After further discussion, at the conclusion of the meeting, the QEP board authorized management and Evercore to agree to the proposed 0.050 per share exchange ratio and to continue negotiating definitive transaction documents, subject to satisfactory completion of due diligence, including financial due diligence. The QEP board also authorized QEP management to enter into the exclusivity agreement with Diamondback through December 24, 2020.

Following the meeting of the QEP board, on that same day, Mr. Cutt called Mr. Stice and informed him that the QEP board had approved the 0.050 exchange ratio.

On that same day, Diamondback entered into formal engagement letters with Goldman and Moelis to assist with the transaction with QEP.

On that same day, Akin Gump sent Latham a revised draft of the merger agreement. Later on that same day, Diamondback received positive preliminary feedback from its ratings agencies. Mr. Stice updated the Diamondback board by email regarding the ratings feedback and his discussions with Mr. Cutt.

On December 18, 2020, Diamondback and QEP signed an exclusivity agreement providing for exclusive negotiations through December 24, 2020.

On that same day, representatives from Latham reviewed and discussed with QEP management key provisions of the revised merger agreement draft that had been provided by Diamondback on December 17, 2020, including the deal protection provisions, the “force the vote” covenant and the proposed termination fee and expense reimbursement obligations of QEP, which were based on QEP’s enterprise value. QEP and representatives from Latham and RLF discussed the revised draft. QEP management provided Latham with direction as to how to respond on key terms of the merger agreement, and authorized Latham to prepare and distribute a revised draft of the merger agreement to Diamondback. Later that day, Latham sent Akin Gump a revised draft of the merger agreement.

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On that same day, Diamondback entered into a definitive agreement with Guidon (the “Guidon Agreement”), an oil exploration and production company, regarding the Pending Guidon Acquisition, and Guidon subsequently approved Diamondback informing QEP about the execution of the Guidon Agreement. Following the execution of the Guidon Agreement, there were a number of communications between Diamondback and QEP and internally at Diamondback and QEP regarding Guidon. First, Messrs. Cutt and Stice had a telephone conversation where Mr. Stice informed Mr. Cutt about the execution of the Guidon Agreement. Then, Messrs. Cutt, Woosley and Buese had a telephone call with representatives of Evercore and Latham to discuss Diamondback’s pending acquisition of all or substantially all of Guidon’s assets and the potential impact on the merger of QEP and Diamondback. Representatives of Latham, RLF and Mr. Woosley also discussed the board’s fiduciary duties in light of the Guidon Agreement. Finally, QEP management and representatives of Evercore, Latham and Goldman had a telephone conference call with Mr. Van’t Hof and other representatives of Diamondback to discuss the Pending Guidon Acquisition and conduct diligence regarding the same.

On the morning of December 19, 2020, Mr. Zmigrosky circulated a summary of the then-current draft of the merger agreement prepared by Akin Gump to the Diamondback board.

On the same day, Mr. Woosley and representatives of Latham had multiple discussions with Mr. Van’t Hof, Mr. Zmigrosky and/or representatives of Akin Gump regarding the terms of the merger agreement, including provisions relating to deal protection and the termination fee, scope of representations and warranties and interim operating covenants. Diamondback and Akin Gump represented that the “force the vote” covenant was a material term to Diamondback and insisted on its inclusion in the merger agreement. Mr. Woosley and Latham acknowledged the request and represented that it would discuss the request with the QEP board.

On that same day, the QEP board held a telephonic board call, along with representatives of management, Evercore and Latham, to continue to discuss a potential transaction between QEP and Diamondback on the basis of a 0.050 exchange ratio. Mr. Cutt provided the board with an update regarding the recent development related to Diamondback’s pending acquisition of Guidon’s assets. Mr. Cutt reminded the board that management had previously evaluated Guidon’s assets several times, including recent technical and financial diligence, and that management was impressed with the quality of Guidon’s assets and the overlap with Diamondback’s and QEP’s acreage in the Midland Basin. The board then received an overview of Guidon’s operations and assets based on information provided by Diamondback. Representatives of Evercore noted that Diamondback confirmed during a diligence session earlier that day that the pending acquisition of Guidon would not be significant from a financial perspective to Diamondback for SEC reporting purposes. Latham then reminded the board of its fiduciary duties under Delaware law that are owed in connection with the proposed transaction with Diamondback. Latham also provided the board with a summary of the Guidon transaction, and the high-level terms of the definitive agreement entered into with Guidon, based on the call earlier that day. The QEP board then asked several questions regarding the Guidon transaction and its impact on the board’s fiduciary duties when evaluating QEP’s transaction with Diamondback, and Latham addressed those questions.

Mr. Woosley and Latham then discussed the material terms of the merger agreement and open issues, including Diamondback’s request to include a “force the vote” provision in the merger agreement. The board asked several questions, and after discussion authorized QEP management to agree to a “force the vote” provision. After further discussion, at the conclusion of the meeting, the QEP board provided Mr. Woosley and Latham with direction as to how to respond on key terms of the merger agreement and authorized management to proceed with the proposed transaction, subject to finalizing the merger agreement and completing diligence.

On December 20, 2020, QEP and Diamondback exchanged emails to discuss their plans on investor relations in connection with the potential transaction, including a joint press release and an investor presentation.

On the same day, Akin Gump and Latham exchanged multiple drafts of, and finalized, the merger agreement.

On the same day, Mr. Zmigrosky circulated an updated summary of the then-current draft of the merger agreement prepared by Akin Gump to the Diamondback board.

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In the evening of December 20, 2020, the Diamondback board held a videoconference meeting, with members of Diamondback management, as well as representatives of Goldman and Akin Gump also in attendance. Members of the Diamondback board, members of Diamondback management and representatives of Goldman discussed the proposed transaction with QEP, including the financial terms thereof and related financial and operational matters. Messrs. Stice and Van’t Hof reviewed their presentation, previously circulated to the board, regarding certain financial and operational matters related to the Pending Guidon Acquisition and the proposed transaction with QEP. Then representatives of Akin Gump reviewed with the Diamondback board materials summarizing the key provisions of the current draft of the merger agreement, which materials were previously circulated to the board. Throughout these presentations and discussions, members of the Diamondback board asked questions of representatives of Goldman, Akin Gump and Diamondback management. Following additional discussion, the Diamondback board unanimously (i) determined that the merger agreement (including the 0.050 exchange ratio) and the transactions contemplated thereby (including the merger and the related share issuance), were fair to, advisable and in the best interests of Diamondback and its stockholders, (ii) approved the merger agreement and the transactions contemplated thereby, and (iii) approved certain related matters, including the preparation and filing with the SEC of a Registration Statement on Form S-4.

In the evening of December 20, 2020, the compensation committee of QEP and representatives of Meridian Compensation Partners, LLC and Alvarez & Marsal Holdings, LLC met via teleconference to consider, discuss and approve the compensation matters related to the proposed transaction with Diamondback.

Following the compensation committee meeting, the QEP board held a meeting via videoconference, together with members of QEP management and representatives of Evercore and Latham in attendance, to approve the compensation matters related to the proposed transaction and to consider the proposed transaction with Diamondback. QEP management provided an update on the status of negotiations with Diamondback. A representative of Latham reviewed with the QEP board materials summarizing the key provisions of the current draft of the merger agreement, which materials were previously provided to the board. Latham noted that in exchange for agreeing to the “force the vote” provision, Mr. Woosley was able to negotiate, among other things, a reduction in the previously discussed termination fee. The board asked several questions, and Latham and QEP management addressed the board’s questions. Representatives of Evercore then provided the board with Evercore’s financial analysis with respect to the proposed combination of Diamondback and QEP and rendered to the QEP board Evercore’s oral opinion, subsequently confirmed in Evercore’s written opinion dated as of December 20, 2020, that as of December 20, 2020 and based upon and subject to the assumptions, limitations, qualifications and conditions described in Evercore’s written opinion, the merger consideration to be received by the holders of the QEP common stock in the merger was fair, from a financial point of view, to such holders. Following additional discussion, the QEP board unanimously (i) determined that the merger agreement and the transactions contemplated thereby, including the merger, were advisable and in the best interests of QEP and its stockholders, (ii) approved the merger agreement and the transactions contemplated thereby, (iii) approved submitting the merger agreement to QEP’s stockholders and (iv) resolved to recommend that QEP’s stockholders approve and adopt the merger agreement.

Following the QEP board meeting, Mr. Cutt informed Mr. Stice that the QEP board had unanimously approved the proposed transaction. Later in the evening on December 20, 2020, the parties executed the merger agreement and, on December 21, 2020, issued a joint press release announcing the transaction.

Diamondback’s Rationale for the Merger

Diamondback believes that the merger with QEP presents Diamondback with the opportunity:

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In addition, Diamondback expects to maintain its investment grade credit ratings following the completion of the merger.

Recommendation of the QEP Board and Reasons for the Merger

By unanimous vote, the QEP board, at a meeting held on December 20, 2020, (i) declared that the merger agreement and the transactions contemplated thereby were fair to, and in the best interests of, QEP and the QEP stockholders, (ii) approved and declared advisable the merger agreement and the transactions contemplated by the merger agreement and (iii) recommended that the QEP stockholders approve and adopt the merger agreement and the transactions contemplated by the merger agreement. The QEP board unanimously recommends that QEP stockholders vote “FOR” the merger proposal and “FOR” the non-binding compensation advisory proposal.

In evaluating the merger agreement, the merger and the other transaction documents (including the transactions contemplated by those documents), the QEP board consulted with QEP’s senior management, outside legal counsel, financial advisors and tax advisors. The QEP board determined that entering into the merger agreement with Diamondback provided the best alternative for maximizing stockholder value reasonably available to QEP, including when compared to continuing to operate on a standalone basis, strategic combinations with other counterparties and potential asset monetization opportunities.

In recommending that QEP stockholders vote their shares of QEP common stock to approve and adopt the merger agreement, the QEP board also considered a number of factors, including the following factors (not necessarily in order of relative importance) that the QEP board viewed as generally positive or favorable to its determination, approval and related recommendation:

Attractive Value and Merger Consideration. The attractive value and nature of the consideration to be received in the merger by QEP stockholders, including the fact that:

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Benefits of a Combined Company. The belief of the QEP board that the combined company resulting from a merger of Diamondback and QEP would be well positioned to achieve future free cash flow growth and generate superior returns for QEP’s former stockholders, is a result of:

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Continuation of Standalone QEP. The QEP board’s consideration of QEP’s business, prospects and other strategic opportunities, and the QEP board’s belief that there are certain risks associated with continuing to operate as a standalone company, including: