QEP Qep Resources Inc

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.

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.

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.”

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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