CXO Concho Resources Inc

Your vote is very important. Approval of the ConocoPhillips issuance proposal by the ConocoPhillips stockholders is a condition to the merger and requires the affirmative vote of a majority of shares of ConocoPhillips common stock present via the ConocoPhillips special meeting website or by proxy at the ConocoPhillips special meeting and entitled to vote on the proposal. ConocoPhillips stockholders are requested to complete, date, sign and return the enclosed proxy in the envelope provided, which requires no postage if mailed in the United States, or to submit their votes by phone or the Internet. Simply follow the instructions provided on the enclosed proxy card. Abstentions will have the same effect as a vote "AGAINST" the ConocoPhillips issuance proposal and broker non-votes will have no effect on the outcome of the vote.

Your vote is very important. Approval of the merger proposal by the Concho stockholders is a condition to the merger and requires the affirmative vote of a majority of the outstanding shares of Concho common stock entitled to vote on the proposal. Concho stockholders are requested to complete, date, sign and return the enclosed proxy in the envelope provided, which requires no postage if mailed in the United States, or to submit their votes by phone or the Internet. Simply follow the instructions provided on the enclosed proxy card. Abstentions, failure to submit a proxy or vote via the Concho special meeting website and broker non-votes will have the same effect as a vote "AGAINST" the merger proposal.

SUMMARY

        This summary highlights selected information included in this joint proxy statement/prospectus and does not contain all of the information that may be important to you. You should read this joint proxy statement/prospectus and its annexes carefully and in its entirety and the other documents to which ConocoPhillips and Concho refer before you decide how to vote with respect to the proposals to be considered and voted on at the special meeting for your company. In addition, ConocoPhillips and Concho incorporate by reference important business and financial information about ConocoPhillips and Concho into this joint proxy statement/prospectus, as further described in the section entitled "Where You Can Find More Information" beginning on page 230. You may obtain the information incorporated by reference into this joint proxy statement/prospectus without charge by following the instructions in the section entitled "Where You Can Find More Information" beginning on page 230. Each item in this summary includes a page reference directing you to a more complete description of that item in this joint proxy statement/prospectus.

Information About the Companies (page 57)

ConocoPhillips

925 N. Eldridge Parkway
Houston, Texas 77079
Phone: (281) 293-1000

        ConocoPhillips is an independent E&P company with operations and activities in 15 countries. ConocoPhillips' diverse, low cost of supply portfolio includes resource-rich unconventional plays in North America; conventional assets in North America, Europe and Asia; LNG developments; oil sands assets in Canada; and an inventory of global conventional and unconventional exploration prospects. Headquartered in Houston, Texas, as of September 30, 2020, ConocoPhillips employed approximately 9,800 people worldwide and had total assets of $63 billion. ConocoPhillips was incorporated in the State of Delaware on November 16, 2001, in connection with, and in anticipation of, the merger between Conoco Inc. and Phillips Petroleum Company. The merger between Conoco Inc. and Phillips Petroleum Company was consummated on August 30, 2002. On May 1, 2012, ConocoPhillips completed the spinoff of its downstream business, Phillips 66.

Concho Resources Inc.

One Concho Center
600 West Illinois Avenue
Midland, Texas 79701
Phone: (432) 683-7443

        Concho, whose legal name is Concho Resources Inc., was incorporated in Delaware in February 2006. Based in Midland, Texas, Concho is an independent oil and natural gas company engaged in the acquisition, development, exploration and production of oil and natural gas properties. Concho's operations are primarily focused in the Permian Basin of West Texas and Southeast New Mexico. The Permian Basin is one of the most prolific oil and natural gas producing regions in the United States and is characterized by an extensive production history, long reserve life, multiple producing horizons and significant recovery potential. Concho's legacy in the Permian Basin provides it with a deep understanding of operating and geological trends. Concho is actively developing its resource base by utilizing long-lateral wells and multi-well pad locations.

Falcon Merger Sub Corp.

c/o ConocoPhillips
925 N. Eldridge Parkway
Houston, Texas 77079
Phone: (281) 293-1000

        Merger Sub, whose legal name is Falcon Merger Sub Corp., is a direct, wholly owned subsidiary of ConocoPhillips. Upon the completion of the merger, Merger Sub will cease to exist. Merger Sub was incorporated in Delaware on October 16, 2020 for the sole purpose of effecting the merger.

The Merger and the Merger Agreement (page 141)

        The terms and conditions of the merger are contained in the merger agreement, which is attached to this document as Annex A and is incorporated by reference herein in its entirety. ConocoPhillips and Concho encourage you to read the merger agreement carefully and in its entirety, as it is the legal document that governs the merger.

        The ConocoPhillips board and Concho board each has unanimously approved the merger agreement and the transactions contemplated by the merger agreement. Pursuant to the terms and subject to the conditions included in the merger agreement, ConocoPhillips has agreed to acquire Concho by means of a merger of Merger Sub with and into Concho, with Concho surviving the merger as a wholly owned subsidiary of ConocoPhillips.

Merger Consideration (page 143)

        As a result of the merger, each eligible share of Concho common stock issued and outstanding immediately prior to the effective time of the merger will be converted into the right to receive 1.46 shares of ConocoPhillips common stock (i.e., the merger consideration).

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

Risk Factors (page 41)

        The merger and an investment in ConocoPhillips common stock involve risks, some of which are related to the transactions contemplated by the merger agreement. You should carefully consider the information about these risks set forth under the section entitled "Risk Factors" beginning on page 41, together with the other information included or incorporated by reference in this joint proxy statement/prospectus, particularly the risk factors contained in ConocoPhillips' and Concho's Annual Reports on Form 10-K and Quarterly Reports on Form 10-Q. Concho stockholders should carefully consider the risks set out in that section before deciding how to vote with respect to the merger proposal and non-binding compensation advisory proposal to be considered and voted on at the Concho special meeting, and ConocoPhillips stockholders should carefully consider the risks set out in that section before deciding how to vote with respect to the ConocoPhillips issuance proposal to be considered and voted on at the ConocoPhillips special meeting. For additional information, see the section entitled "Where You Can Find More Information" beginning on page 230.

Treatment of Concho Equity Awards (page 143)

Concho Restricted Stock

        At the effective time of the merger, each outstanding award of shares of Concho restricted stock (other than those awards that fully vest by their terms at the effective time) granted under the Concho stock plan will be converted into an award in respect of the number of shares of restricted common stock of ConocoPhillips equal to the product, rounded to the nearest whole share, of the number of shares of Concho common stock subject to the award multiplied by the exchange ratio. Each outstanding award of Concho restricted stock that fully vests by its terms at the effective time will vest and be converted into the right to receive the merger consideration in respect of each share subject to the award.

Concho Performance Units

        At the effective time of the merger, each outstanding award of shares of Concho performance units (other than those awards that might be granted following October 18, 2020) will vest and be converted into the right to receive an amount in cash equal to the value of the merger consideration in respect of each share subject to the award. Applicable performance goals for such Concho performance units will be deemed satisfied at two-thirds (²/3) of maximum performance (which is 200% of target) for active employees and any former employee who, as of the effective time of the merger, serves on the Concho board, and based on actual performance for former employees (and, for former employees, the number of shares subject to the award will be prorated to the extent contemplated by the applicable award agreement). Each outstanding Concho performance unit granted after October 18, 2020 will be converted into a time-vesting award in respect of a number of shares of restricted common stock of ConocoPhillips equal to the product, rounded to the nearest whole share, of the target number of shares of Concho common stock subject to the award multiplied by the exchange ratio. The cash value of the merger consideration will be determined based on the volume weighted average price of ConocoPhillips common stock for the five (5) consecutive trading days ending two (2) trading days prior to the closing date as reported by Bloomberg, L.P.

Recommendation of the ConocoPhillips Board of Directors and Reasons for the Merger (page 86)

        The ConocoPhillips board unanimously recommends that you vote "FOR" the ConocoPhillips issuance proposal. For the factors considered by the ConocoPhillips board in reaching this decision and additional information on the recommendation of the ConocoPhillips board, see the section entitled "The Merger—Recommendation of the ConocoPhillips Board of Directors and Reasons for the Merger" beginning on page 86.

Recommendation of the Concho Board of Directors and Reasons for the Merger (page 98)

        The Concho board unanimously recommends that you vote "FOR" the merger proposal and "FOR" the non-binding compensation advisory proposal. For the factors considered by the Concho board in reaching this decision and additional information on the recommendation of the Concho board, see the section entitled "The Merger—Recommendation of the Concho Board of Directors and Reasons for the Merger" beginning on page 98.

Opinions of Financial Advisors (pages 90, 103 and 111)

Opinion of Goldman Sachs, ConocoPhillips' financial advisor

        At a meeting of the ConocoPhillips board, Goldman Sachs & Co. LLC (which we refer to as "Goldman Sachs") rendered to the ConocoPhillips board its oral opinion, subsequently confirmed by delivery of a written opinion, dated October 18, 2020, to the ConocoPhillips board, to the effect that,

as of the date of Goldman Sachs' written opinion, and based upon and subject to the factors and assumptions set forth in Goldman Sachs' written opinion, the exchange ratio pursuant to the merger agreement was fair from a financial point of view to ConocoPhillips.

        The full text of the written opinion of Goldman Sachs, dated October 18, 2020, which sets forth the assumptions made, procedures followed, matters considered, qualifications and limitations on the review undertaken in connection with the opinion, is attached to this joint proxy statement/prospectus as Annex B. The summary of Goldman Sachs' opinion contained in this joint proxy statement/prospectus is qualified in its entirety by reference to the full text of Goldman Sachs' written opinion. Goldman Sachs' advisory services and opinion were provided for the information and assistance of the ConocoPhillips board in connection with its consideration of the merger and the opinion does not constitute a recommendation as to how any ConocoPhillips stockholder should vote with respect to the merger or any other matter.

        For additional information, see the section entitled "The Merger—Opinion of Goldman Sachs, ConocoPhillips' Financial Advisor" beginning on page 90 and the full text of the written opinion of Goldman Sachs attached as Annex B to this joint proxy statement/prospectus.

Opinion of Credit Suisse, Concho's financial advisor

        On October 18, 2020, Credit Suisse Securities (USA) LLC (which we refer to as "Credit Suisse") rendered its oral opinion to the Concho board (which was subsequently confirmed in writing by delivery of Credit Suisse's written opinion addressed to the Concho board dated the same date) as to, as of October 18, 2020, the fairness, from a financial point of view, to the holders of Concho common stock of the exchange ratio in the merger pursuant to the merger agreement.

        Credit Suisse's opinion was directed to the Concho board (in its capacity as such), and only addressed the fairness, from a financial point of view, to the holders of Concho common stock of the exchange ratio in the merger pursuant to the merger agreement and did not address any other aspect or implication (financial or otherwise) of the merger. The summary of Credit Suisse's opinion in this joint proxy statement/prospectus is qualified in its entirety by reference to the full text of its written opinion, which is included as Annex C to this joint proxy statement/prospectus and sets forth the procedures followed, assumptions made, qualifications and limitations on the review undertaken and other matters considered by Credit Suisse in preparing its opinion. However, neither Credit Suisse's written opinion nor the summary of its opinion and the related analyses set forth in this joint proxy statement/prospectus are intended to be, and they do not constitute, advice or a recommendation to any stockholder as to how such holder should vote or act on any matter relating to the merger.

        For additional information, see the section entitled "The Merger—Opinion of Credit Suisse, Concho's Financial Advisor" beginning on page 103 and the full text of the written opinion of Credit Suisse attached as Annex C of this joint proxy statement/prospectus.

Opinion of J.P. Morgan, Concho's financial advisor

        At the meeting of the Concho board on October 18, 2020, J.P. Morgan Securities LLC (which we refer to as "J.P. Morgan") rendered its oral opinion to the Concho board (which was subsequently confirmed in writing by delivery of J.P. Morgan's written opinion addressed to the Concho board dated the same date) as to, as of October 18, 2020, the fairness, from a financial point of view, to the holders of Concho common stock of the exchange ratio in the merger pursuant to the merger agreement.

        The full text of the written opinion of J.P. Morgan, dated October 18, 2020, which sets forth the assumptions made, matters considered and limits on the review undertaken, is attached as Annex D to this joint proxy statement/prospectus and is incorporated herein by reference. The summary of the opinion of J.P. Morgan set forth in this joint proxy statement/prospectus is qualified in its entirety by

reference to the full text of such opinion. J.P. Morgan's written opinion was addressed to the Concho board (in its capacity as such) in connection with and for the purposes of its evaluation of the merger, was directed only to the exchange ratio to be paid to the holders of Concho common stock in the merger and did not address any other aspect of the merger. The opinion does not constitute a recommendation to any stockholder of Concho as to how such stockholder should vote with respect to the merger or any other matter.

        For additional information, see the section entitled "The Merger—Opinion of J.P. Morgan, Concho's Financial Advisor" beginning on page 111 and the full text of the written opinion of J.P. Morgan attached as Annex D of this joint proxy statement/prospectus.

Special Meeting of ConocoPhillips Stockholders (page 58)

Date, Time, Place and Purpose of the ConocoPhillips Special Meeting

        The ConocoPhillips special meeting will be held virtually via the Internet on January 15, 2021, at 9:00 a.m., Central Time. In light of ongoing developments related to the COVID-19 (coronavirus) pandemic and to be consistent with ConocoPhillips' SPIRIT values, ConocoPhillips has elected to hold the ConocoPhillips special meeting solely by means of remote communication via the Internet. The ConocoPhillips special meeting will be held solely via live webcast and there will not be a physical meeting location. ConocoPhillips stockholders will be able to attend the ConocoPhillips special meeting online and vote their shares electronically during the meeting by visiting www.virtualshareholdermeeting.com/COP2021SM, which we refer to as the "ConocoPhillips special meeting website."

        The purpose of the ConocoPhillips special meeting is to consider and vote on the ConocoPhillips issuance proposal. Approval of the ConocoPhillips issuance proposal is a condition to the obligation of ConocoPhillips and Concho to complete the merger.

Record Date and Outstanding Shares of ConocoPhillips Common Stock

        Only holders of record of issued and outstanding shares of ConocoPhillips common stock as of the close of business on December 11, 2020, the record date for the ConocoPhillips special meeting, are entitled to notice of, and to vote at, the ConocoPhillips special meeting via the ConocoPhillips special meeting website or any adjournment or postponement of the ConocoPhillips special meeting.

        As of December 9, 2020 (the last practicable date prior to the record date), there were 1,068,034,619 shares of ConocoPhillips common stock issued and outstanding and entitled to vote at the ConocoPhillips special meeting. You may cast one vote for each share of ConocoPhillips common stock that you held as of the close of business on the record date.

        A complete list of ConocoPhillips stockholders entitled to vote at the ConocoPhillips special meeting will be available for inspection at ConocoPhillips' offices in Houston, Texas during ordinary business hours for a period of no less than 10 days before the ConocoPhillips special meeting. If you would like to examine the list of ConocoPhillips stockholders, please contact the ConocoPhillips Corporate Secretary at (281) 293-3030. If ConocoPhillips' headquarters are closed for health and safety reasons related to the COVID-19 (coronavirus) pandemic during such period, the list of ConocoPhillips stockholders will be made available for inspection upon request to the ConocoPhillips Corporate Secretary, subject to the satisfactory verification of stockholder status. The list of ConocoPhillips stockholders entitled to vote at the ConocoPhillips special meeting will also be made available for inspection during the ConocoPhillips special meeting via the ConocoPhillips special meeting website at www.virtualshareholdermeeting.com/COP2021SM.

Quorum; Abstentions and Broker Non-Votes

        A quorum of ConocoPhillips stockholders is necessary for ConocoPhillips to hold a valid meeting. The presence at the ConocoPhillips special meeting, via the ConocoPhillips special meeting website or by proxy, of the shares of ConocoPhillips common stock entitled to cast a majority of the votes which could be cast at the ConocoPhillips special meeting by the holders of all the outstanding shares of ConocoPhillips common stock entitled to vote at such meeting constitutes a quorum. If you submit a properly executed proxy card, even if you do not vote for the proposal or vote to "abstain" in respect of the proposal, your shares of ConocoPhillips common stock will be counted for purposes of calculating whether a quorum is present for the transaction of business at the ConocoPhillips special meeting.

        ConocoPhillips 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 ConocoPhillips common stock with respect to which the beneficial owner otherwise fails to vote, will not be considered present and entitled to vote at the ConocoPhillips 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. It is not expected that there will be any broker non-votes at the ConocoPhillips special meeting. However, if there are any broker non-votes, the shares will not be considered present and entitled to vote at the ConocoPhillips special meeting for the purpose of determining the presence of a quorum.

        Executed but unvoted proxies will be voted in accordance with the recommendation of the ConocoPhillips board.

Required Vote to Approve the ConocoPhillips Issuance Proposal

        Approval of the ConocoPhillips issuance proposal requires the affirmative vote of a majority of shares of ConocoPhillips common stock present via the ConocoPhillips special meeting website or by proxy at the ConocoPhillips special meeting and entitled to vote on the proposal. Abstentions will have the same effect as a vote "AGAINST" the proposal, and broker non-votes will have no effect on the outcome of the vote.

        The ConocoPhillips issuance proposal is described in the section entitled "ConocoPhillips Stockholder Proposal" beginning on page 63.

Voting by Directors and Executive Officers

        As of December 2, 2020, ConocoPhillips directors and executive officers, and their affiliates, as a group, owned and were entitled to vote 337,082 shares of ConocoPhillips common stock, or less than 1% of the total outstanding shares of ConocoPhillips common stock as of December 2, 2020.

        ConocoPhillips currently expects that all of its directors and executive officers will vote their shares "FOR" the ConocoPhillips issuance proposal.

Adjournment

        If a quorum is not present or if there are not sufficient votes for the approval of the ConocoPhillips issuance proposal, ConocoPhillips expects that the ConocoPhillips special meeting will be adjourned by the chairman of the ConocoPhillips special meeting to solicit additional proxies in accordance with the merger agreement. At any subsequent reconvening of the ConocoPhillips special meeting, all proxies will be voted in the same manner as the manner in which such proxies would have

been voted at the original convening of the ConocoPhillips special meeting, except for any proxies that have been validly revoked or withdrawn prior to the subsequent meeting.

Special Meeting of Concho Stockholders (page 64)

Date, Time, Place and Purpose of the Concho Special Meeting

        The Concho special meeting will be held virtually via the Internet on January 15, 2021, at 9:00 a.m., Central Time. In light of ongoing developments related to the COVID-19 (coronavirus) pandemic, the Concho special meeting will be held solely via live webcast and there will not be a physical meeting location. Concho stockholders will be able to attend the Concho special meeting online and vote their shares electronically during the meeting by visiting www.virtualshareholdermeeting.com/CXO2021SM, which we refer to as the "Concho special meeting website."

        The purpose of the Concho special meeting is to consider and vote on the merger proposal and the non-binding compensation advisory proposal. Approval of the merger proposal is a condition to the obligation of Concho and ConocoPhillips to complete the merger. Approval of the non-binding compensation advisory proposal is not a condition to the obligation of either Concho or ConocoPhillips to complete the merger.

Record Date and Outstanding Shares of Concho Common Stock

        Only holders of record of issued and outstanding shares of Concho common stock as of the close of business on December 11, 2020, the record date for the Concho special meeting, are entitled to notice of, and to vote at, the Concho special meeting via the Concho special meeting website or any adjournment or postponement of the Concho special meeting.

        As of December 9, 2020 (the last practicable date prior to the record date), there were 196,294,626 shares of Concho common stock issued and outstanding and entitled to vote at the Concho special meeting. You may cast one vote for each share of Concho common stock that you held as of the close of business on the record date.

        A complete list of Concho stockholders entitled to vote at the Concho special meeting will be available for inspection at Concho's principal place of business during regular business hours for a period of no less than 10 days before the Concho special meeting at One Concho Center, 600 West Illinois Avenue, Midland, Texas 79701. If Concho's headquarters are closed for health and safety reasons related to the COVID-19 (coronavirus) pandemic during such period, the list of Concho stockholders will be made available for inspection upon request to Concho's corporate secretary, subject to the satisfactory verification of stockholder status. The list of Concho stockholders entitled to vote at the Concho special meeting will also be made available for inspection during the Concho special meeting via the Concho special meeting website at www.virtualshareholdermeeting.com/CXO2021SM.

Quorum; Abstentions and Broker Non-Votes

        A quorum of Concho stockholders is necessary for Concho to hold a valid meeting. The presence at the Concho special meeting, via the Concho special meeting website or by proxy, of the holders of a majority of the outstanding shares of Concho common stock entitled to vote at the Concho special meeting constitutes a quorum.

        If you submit a properly executed proxy card, even if you do not vote for either proposal or vote to "abstain" in respect of each proposal, your shares of Concho common stock will be counted for purposes of calculating whether a quorum is present for the transaction of business at the Concho special meeting. Concho 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 Concho common stock with respect to which the beneficial owner otherwise fails to vote, will not be considered present and entitled to vote at the Concho 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. It is not expected that there will be any broker non-votes at the Concho special meeting. However, if there are any broker non-votes, the shares will not be considered present and entitled to vote at the Concho 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 Concho board.

Required Vote to Approve the Merger Proposal

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

        The merger proposal is described in the section entitled "Concho Proposals" beginning on page 69.

Required Vote to Approve 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 Concho common stock present via the Concho special meeting website or represented by proxy at the Concho special meeting and entitled to vote on the proposal. Abstentions will have the same effect as a vote "AGAINST" the proposal, and broker non-votes will have no effect on the outcome of the vote.

        The non-binding compensation advisory proposal is described in the section entitled "Concho Proposals" beginning on page 69.

Voting by Directors and Executive Officers

        As of December 2, 2020, Concho directors and executive officers, and their affiliates, as a group, owned and were entitled to vote 1,806,252 shares of Concho common stock, or less than 1% of the total outstanding shares of Concho common stock as of December 2, 2020.

        Concho currently expects that all of its directors and executive officers will vote their shares "FOR" the merger proposal and "FOR" the non-binding compensation advisory proposal.

Adjournment

        If a quorum is not present or if there are not sufficient votes for the approval of the merger proposal, Concho expects that the Concho special meeting will be adjourned by the chairman of the Concho special meeting to solicit additional proxies in accordance with the merger agreement. At any subsequent reconvening of the Concho special meeting, all proxies will be voted in the same manner as the manner in which such proxies would have been voted at the original convening of the Concho special meeting, except for any proxies that have been validly revoked or withdrawn prior to the subsequent meeting.

Board of Directors and Management of ConocoPhillips Following the Completion of the Merger (page 130)

        Under the terms of the merger agreement, ConocoPhillips has agreed to take all necessary corporate action so that upon and after the effective time of the merger, the size of the ConocoPhillips board is increased by one member, and prior to the completion of the merger, Concho's Chairman and Chief Executive Officer as of the date of the merger agreement (provided he remains in such positions as of immediately prior to the completion of the merger or else a member of the Concho board mutually agreed between Concho and ConocoPhillips) is appointed to the ConocoPhillips board to fill the vacancy on the ConocoPhillips board created by such increase. ConocoPhillips, through the ConocoPhillips board, has agreed to take all necessary action to nominate such new director for election to the ConocoPhillips board in the proxy statement relating to the first annual meeting of the stockholders of ConocoPhillips following the completion of the merger.

        Upon the completion of the merger, the current directors and executive officers of ConocoPhillips are expected to continue in their current positions, other than as may be publicly announced by ConocoPhillips in the normal course and other than as a result of Concho's Chairman and Chief Executive Officer becoming Executive Vice President, Lower 48 of ConocoPhillips, Concho's President becoming President, Permian of ConocoPhillips and Concho's Executive Vice President and Chief Operating Officer becoming Vice President and Chief Commercial Officer of ConocoPhillips, in each case, effective upon the effective time of the merger.

Interests of Concho Directors and Executive Officers in the Merger (page 130)

        In considering the recommendation of the Concho board with respect to the merger proposal and the non-binding compensation advisory proposal, Concho stockholders should be aware that the directors and executive officers of Concho have interests in the merger that may be different from, or in addition to, the interests of Concho stockholders generally. The members of the Concho board were aware of and considered these interests, among other matters, in evaluating and negotiating the merger agreement, in approving the merger agreement and in determining to recommend that Concho stockholders approve the merger proposal.

Conditions to the Completion of the Merger (page 179)

        Each party's obligation to complete the merger is subject to the satisfaction or waiver of the following mutual conditions:

•

ConocoPhillips Stockholder Approval.  The ConocoPhillips issuance proposal must have been approved in accordance with applicable law and the ConocoPhillips organizational documents, as applicable.



•

Concho Stockholder Approval.  The merger proposal must have been approved in accordance with applicable law and the Concho organizational documents, as applicable.



•

Regulatory Approval.  Any waiting period under the Hart-Scott-Rodino Antitrust Improvements Act of 1976, as amended (which we refer to as the "HSR Act") applicable to the merger and the other transactions contemplated by the merger agreement must have expired or been terminated.



•

No Injunctions or Restraints.  Any governmental entity having jurisdiction over ConocoPhillips, Concho and Merger Sub must not have issued any order, decree, ruling, injunction or other action that is in effect (whether temporary, preliminary or permanent) restraining, enjoining or otherwise prohibiting the consummation of the merger and any law that makes the consummation of the merger illegal or otherwise prohibited must not have been adopted.

•

Effectiveness of the Registration Statement.  The registration statement, of which this joint proxy statement/prospectus forms a part, must have been declared effective by the SEC under the Securities Act and must not be the subject of any stop order or proceedings seeking a stop order.



•

NYSE Listing.  The shares of ConocoPhillips common stock issuable to Concho stockholders pursuant to the merger agreement must have been authorized for listing on the NYSE, upon official notice of issuance.

        The obligations of ConocoPhillips and Merger Sub to complete the merger are subject to the satisfaction or waiver of further conditions, including:

•

the accuracy of the representations and warranties of Concho contained in the merger agreement as of October 18, 2020 and as of the closing date (other than representations that by their terms speak specifically as of another date or period of time), subject to the materiality standards provided in the merger agreement;



•

Concho having performed and complied with in all material respects all of its obligations under the merger agreement required to be performed or complied with at or prior to the effective time of the merger; and



•

ConocoPhillips having received a certificate of Concho signed by an executive officer of Concho, dated as of the closing date, confirming that the conditions set forth in the two bullets directly above have been satisfied.

        The obligation of Concho to complete the merger is subject to the satisfaction or waiver of the following additional conditions:

•

the accuracy of the representations and warranties of ConocoPhillips contained in the merger agreement as of October 18, 2020 and as of the closing date (other than representations that by their terms speak specifically as of another date or period of time), subject to the materiality standards provided in the merger agreement;



•

ConocoPhillips and Merger Sub having performed and complied with in all material respects all of their respective obligations under the merger agreement required to be performed or complied with by them at or prior to the effective time of the merger; and



•

Concho having received a certificate of ConocoPhillips signed by an executive officer of ConocoPhillips, dated as of the closing date, confirming that the conditions in the two bullets directly above have been satisfied.

No Solicitation (page 155)

No Solicitation by ConocoPhillips

        ConocoPhillips has agreed that, from and after October 18, 2020, ConocoPhillips and its officers and directors will, will cause ConocoPhillips' subsidiaries and their respective officers and directors to, and will use their reasonable best efforts to cause the other representatives of ConocoPhillips and its subsidiaries to, immediately cease, and cause to be terminated, any discussion or negotiations ongoing with any person with respect to any inquiry, proposal or offer that constitutes, or would reasonably be expected to lead to, a ConocoPhillips competing proposal (as such term is defined in the section entitled "The Merger Agreement—No Solicitation; Changes of Recommendation—Definitions of Competing Proposals" beginning on page 166).

        ConocoPhillips has also agreed that, from and after October 18, 2020, ConocoPhillips and its officers and directors will not, will cause ConocoPhillips' subsidiaries and their respective officers and

directors not to, and will use their reasonable best efforts to cause the other representatives of ConocoPhillips and its subsidiaries not to:

•

initiate, solicit, propose, knowingly encourage, or knowingly facilitate any inquiry or the making of any proposal or offer that constitutes, or could reasonably be expected to result in, a ConocoPhillips competing proposal;



•

engage in, continue or otherwise participate in any discussions with any person with respect to or negotiations with any person with respect to, relating to, or in furtherance of a ConocoPhillips competing proposal or any inquiry, proposal or offer that could reasonably be expected to lead to a ConocoPhillips competing proposal;



•

furnish any information regarding ConocoPhillips or its subsidiaries, or access to the properties, assets or employees of ConocoPhillips or its subsidiaries, to any person in connection with or in response to any ConocoPhillips competing proposal or any inquiry, proposal or offer that could reasonably be expected to lead to a ConocoPhillips competing proposal;



•

enter into any letter of intent or agreement in principal, or other agreement providing for a ConocoPhillips competing proposal (other than certain confidentiality agreements entered into as permitted by the merger agreement); or



•

submit any ConocoPhillips competing proposal to the vote of ConocoPhillips stockholders.

        Notwithstanding the agreements described above, prior to, but not after, the time the ConocoPhillips issuance proposal has been approved by ConocoPhillips stockholders, ConocoPhillips may engage in the second and third bullets directly above with any person if (i) ConocoPhillips receives a bona fide written ConocoPhillips competing proposal from such person that was not solicited at any time following October 18, 2020; and (ii) such ConocoPhillips competing proposal did not arise from a breach of the obligations described directly above and in the section entitled "The Merger Agreement—No Solicitation; Changes of Recommendation—Definitions of Competing Proposals" beginning on page 166; provided, however, that:

•

no information that is prohibited from being furnished pursuant to the foregoing obligations may be furnished until ConocoPhillips receives an executed confidentiality agreement, subject to certain conditions;



•

any non-public information furnished to any person will have previously been made available to Concho, or is made available to Concho prior to or concurrently with the time such information is made available to such person;



•

prior to taking any such actions, the ConocoPhillips board or any committee of the ConocoPhillips board determines in good faith, after consultation with its financial advisors and outside legal counsel, that such ConocoPhillips competing proposal is, or would reasonably be expected to lead to, a ConocoPhillips superior proposal (as defined in the section entitled "The Merger Agreement—No Solicitation; Changes of Recommendation" beginning on page 155); and



•

prior to taking any such actions, the ConocoPhillips board determines in good faith after consultation with its outside legal counsel that failure to take such action would be inconsistent with the fiduciary duties owed by the ConocoPhillips board to the stockholders of ConocoPhillips under applicable law.

        Notwithstanding the above restrictions, ConocoPhillips may, in response to an inquiry or proposal from a third party, inform a third party or its representative of the "no solicitation" obligations described above (without conveying, requesting or attempting to gather any other information except as otherwise specifically permitted under the merger agreement).

No Solicitation by Concho

        Concho has agreed that, from and after October 18, 2020, Concho and its officers and directors will, will cause Concho's subsidiaries and their respective officers and directors to, and will use their reasonable best efforts to cause the other representatives of Concho and its subsidiaries to, immediately cease, and cause to be terminated, any discussion or negotiations ongoing with any third party with respect to any inquiry, proposal or offer that constitutes, or would reasonably be expected to lead to, a Concho competing proposal (as such term is defined in the section entitled "The Merger Agreement—No Solicitation; Changes of Recommendation—Definitions of Competing Proposals" beginning on page 166).

        Concho has also agreed that, from and after October 18, 2020, Concho and its officers and directors will not, will cause Concho's subsidiaries and their respective officers and directors not to, and will use their reasonable best efforts to cause the other representatives of Concho and its subsidiaries not to:

•

initiate, solicit, propose, knowingly encourage, or knowingly facilitate any inquiry or the making of any proposal or offer that constitutes, or could reasonably be expected to result in, a Concho competing proposal;



•

engage in, continue or otherwise participate in any discussions with any person with respect to or negotiations with any person with respect to, relating to, or in furtherance of a Concho competing proposal or any inquiry, proposal or offer that could reasonably be expected to lead to a Concho competing proposal;



•

furnish any information regarding Concho or its subsidiaries, or access to the properties, assets or employees of Concho or its subsidiaries, to any person in connection with or in response to any Concho competing proposal or any inquiry, proposal or offer that could reasonably be expected to lead to a Concho competing proposal;



•

enter into any letter of intent or agreement in principal, or other agreement providing for a Concho competing proposal (other than certain confidentiality agreements entered into as permitted by the merger agreement); or



•

submit any Concho competing proposal to the vote of Concho stockholders.

        Notwithstanding the agreements described above, prior to, but not after, the time the merger proposal has been approved by Concho stockholders, Concho may engage in the second and third bullets directly above with any person if (i) Concho receives a bona fide written Concho competing proposal from such person that was not solicited at any time following October 18, 2020; and (ii) such Concho competing proposal did not arise from a breach of the obligations described directly above and in the section entitled "The Merger Agreement—No Solicitation; Changes of Recommendation—Definitions of Competing Proposals" beginning on page 166; provided, however, that:

•

no information that is prohibited from being furnished pursuant to the foregoing obligations may be furnished until Concho receives an executed confidentiality agreement, subject to certain conditions;



•

any non-public information furnished to any person will have previously been made available to ConocoPhillips or is made available to ConocoPhillips prior to or concurrently with the time such information is made available to such person;



•

prior to taking any such actions, the Concho board or any committee of the Concho board determines in good faith, after consultation with its financial advisors and outside legal counsel, that such Concho competing proposal is, or would reasonably be expected to lead to, a Concho superior proposal (as defined in the section entitled "The Merger Agreement—No Solicitation; Changes of Recommendation" beginning on page 155); and

•

prior to taking any such actions, the Concho board determines in good faith after consultation with its outside legal counsel that failure to take such action would be inconsistent with the fiduciary duties owed by the Concho board to the stockholders of Concho under applicable law.

        Notwithstanding the above restrictions, Concho may, in response to an inquiry or proposal from a third party, inform a third party or its representative of the "no solicitation" obligations described above (without conveying, requesting or attempting to gather any other information except as otherwise specifically permitted under the merger agreement).

Changes of Recommendation (page 155)

ConocoPhillips Restrictions on Changes of Recommendation

        Subject to certain exceptions described below, the ConocoPhillips board may not effect a ConocoPhillips recommendation change (as defined in the section entitled "The Merger Agreement—No Solicitation; Changes of Recommendation—ConocoPhillips: Restrictions on Changes of Recommendation" beginning on page 159).

Concho Restrictions on Changes of Recommendation

        Subject to certain exceptions described below, the Concho board may not effect a Concho recommendation change (as defined in the section entitled "The Merger Agreement—No-Solicitation; Changes of Recommendation—Concho: Restrictions on Changes of Recommendation" beginning on page 160).

ConocoPhillips: Permitted Changes of Recommendation in Connection with a ConocoPhillips Superior Proposal

        Prior to, but not after, the time that the ConocoPhillips issuance proposal has been approved by ConocoPhillips stockholders, in response to a bona fide written ConocoPhillips competing proposal from a third party that was not solicited at any time following October 18, 2020, that is expressly conditioned upon the non-consummation of the transactions contemplated by the merger agreement (including the failure to satisfy any of the closing conditions required by the merger agreement), and did not arise from a breach of the "no solicitation" obligations described above and in the section entitled "The Merger Agreement—No Solicitation; Changes of Recommendation—No Solicitation by ConocoPhillips" beginning on page 155 the ConocoPhillips board may effect a ConocoPhillips recommendation change (but may not terminate the merger agreement) if:

•

the ConocoPhillips board determines in good faith, after consultation with its financial advisors and outside legal counsel, that such ConocoPhillips competing proposal is a ConocoPhillips superior proposal and, after consultation with its outside legal counsel, that the failure to effect a ConocoPhillips recommendation change in response to such ConocoPhillips superior proposal would be inconsistent with the fiduciary duties owed by the ConocoPhillips board to the stockholders of ConocoPhillips under applicable law; and



•

ConocoPhillips provides Concho written notice of such proposed action and the basis of such proposed action three business days in advance and complies with certain obligations, each as described in the section entitled "The Merger Agreement—No Solicitation; Changes of Recommendation—ConocoPhillips: Permitted Changes of Recommendation in Connection with a ConocoPhillips Superior Proposal" beginning on page 161.

ConocoPhillips: Permitted Changes of Recommendation in Connection with Intervening Events

        Prior to, but not after, the time the ConocoPhillips issuance proposal has been approved by ConocoPhillips stockholders, in response to a ConocoPhillips intervening event (as defined in the

section entitled "The Merger Agreement—No Solicitation; Changes of Recommendation—ConocoPhillips: Permitted Changes of Recommendation in Connection with Intervening Events" beginning on page 162) that occurs or arises after October 18, 2020 and that did not arise from or in connection with a breach of the merger agreement by ConocoPhillips, ConocoPhillips may effect a ConocoPhillips recommendation change (but may not terminate the merger agreement) if:

•

the ConocoPhillips board determines in good faith, after consultation with its financial advisors and outside legal counsel, that a ConocoPhillips intervening event has occurred and, after consultation with its outside legal counsel, that failure to effect a ConocoPhillips recommendation change in response to such ConocoPhillips intervening event would be inconsistent with the fiduciary duties owed by the ConocoPhillips board to the stockholders of ConocoPhillips under applicable law; and



•

ConocoPhillips provides Concho written notice of such proposed action and the basis of such proposed action three business days in advance (including a reasonably detailed description of the facts and circumstances of the ConocoPhillips intervening event) and complies with certain obligations, each as described in the section entitled "The Merger Agreement—No Solicitation; Changes of Recommendation—ConocoPhillips: Permitted Changes of Recommendation in Connection with Intervening Events" beginning on page 162.

Concho: Permitted Changes of Recommendation in Connection with a Concho Superior Proposal

        Prior to, but not after, the time the merger proposal has been approved by Concho stockholders, in response to a bona fide written Concho competing proposal from a third party that was not solicited at any time following October 18, 2020 and did not arise from a breach of the "no solicitation" obligations described above and in the section entitled "The Merger Agreement—No Solicitation; Changes of Recommendation—No Solicitation by Concho" beginning on page 157, the Concho board may effect a Concho recommendation change (but may not terminate the merger agreement) if:

•

the Concho board determines in good faith, after consultation with its financial advisors and outside legal counsel, that such Concho competing proposal is a Concho superior proposal and, after consultation with its outside legal counsel, that the failure to effect a Concho recommendation change in response to such Concho superior proposal would be inconsistent with the fiduciary duties owed by the Concho board to the stockholders of Concho under applicable law; and



•

Concho provides ConocoPhillips written notice of such proposed action and the basis of such proposed action three business days in advance and complies with certain obligations, each as described in the section entitled "The Merger Agreement—No Solicitation; Changes of Recommendation—Concho: Permitted Changes of Recommendation in Connection with a Concho Superior Proposal" beginning on page 163.

Concho: Permitted Changes of Recommendation in Connection with Intervening Events

        Prior to, but not after, the time the merger proposal has been approved by Concho stockholders, in response to a Concho intervening event (as defined in the section entitled "The Merger Agreement—No Solicitation; Changes of Recommendation—Concho: Permitted Changes of Recommendation in Connection with Intervening Events" beginning on page 164) that occurs or arises after October 18, 2020 and that did not arise from or in connection with a breach of the merger agreement by Concho, Concho may effect a Concho recommendation change (but may not terminate the merger agreement) if:

•

the Concho board determines in good faith, after consultation with its financial advisors and outside legal counsel, that a Concho intervening event has occurred and, after consultation with

its outside legal counsel, that failure to effect a Concho recommendation change in response to such Concho intervening event would be inconsistent with the fiduciary duties owed by the Concho board to the stockholders of Concho under applicable law; and

•

Concho provides ConocoPhillips written notice of such proposed action and the basis of such proposed action three business days in advance (including a reasonably detailed description of the facts and circumstances of the Concho intervening event) and complies with certain obligations, each as described in the section entitled "The Merger Agreement—No Solicitation; Changes of Recommendation—Concho: Permitted Changes of Recommendation in Connection with Intervening Events" beginning on page 164.

Termination (page 181)

        ConocoPhillips and Concho may terminate the merger agreement and abandon the merger at any time prior to the effective time of the merger by mutual written consent of ConocoPhillips and Concho.

        The merger agreement may also be terminated by either ConocoPhillips or Concho at any time prior to the effective time of the merger in any of the following situations:

•

if any governmental entity having jurisdiction over any party has issued any order, decree, ruling or injunction or taken any other action permanently restraining, enjoining or otherwise prohibiting the consummation of the merger and such order, decree, ruling or injunction or other action has become final and nonappealable, or if any law has been adopted that permanently makes the consummation of the merger illegal or otherwise permanently prohibited, so long as the terminating party has not breached any material covenant or agreement under the merger agreement that has caused or resulted in such order, decree, ruling or injunction or other action;



•

upon an end date termination event (as defined in the section entitled "The Merger Agreement—Termination—Termination Rights" beginning on page 181); or



•

upon a Concho stockholder approval termination event or a ConocoPhillips stockholder approval termination event (as each term is defined in the section entitled "The Merger Agreement—Termination—Termination Rights" beginning on page 181).

        In addition, the merger agreement may be terminated by ConocoPhillips:

•

if prior to, but not after, the time the merger proposal has been approved by Concho stockholders, the Concho board or a committee of the Concho board has effected a Concho recommendation change;



•

upon a Concho breach termination event (as defined in the section entitled "The Merger Agreement—Termination—Termination Rights" beginning on page 181); or



•

upon a Concho no solicitation breach termination event (as defined in the section entitled "The Merger Agreement—Termination—Termination Rights" beginning on page 181).

        Further, the merger agreement may be terminated by Concho:

•

if prior to, but not after, the time the ConocoPhillips issuance proposal has been approved by ConocoPhillips stockholders, the ConocoPhillips board or a committee of the ConocoPhillips board has effected a ConocoPhillips recommendation change;



•

upon a ConocoPhillips breach termination event (as defined in the section entitled "The Merger Agreement—Termination—Termination Rights" beginning on page 181); or



•

upon a ConocoPhillips no solicitation breach termination event (as defined in the section entitled "The Merger Agreement—Termination—Termination Rights" beginning on page 181).

Termination Fees (page 182)

Termination Fees Payable by ConocoPhillips

        The merger agreement requires ConocoPhillips to pay Concho a termination fee of $450 million (which we refer to as the "reverse termination fee") if:

•

Concho terminates the merger agreement due to a ConocoPhillips recommendation change or due to a ConocoPhillips no solicitation breach termination event; or



•

(i) (A) ConocoPhillips or Concho terminates the merger agreement due to a ConocoPhillips stockholder approval termination event, and on or before the date of any such termination, a ConocoPhillips competing proposal was publicly announced or publicly disclosed and was not publicly withdrawn without qualification at least seven business days prior to the ConocoPhillips special meeting or (B) Concho or ConocoPhillips terminates the merger agreement due to an end date termination event or Concho terminates the merger agreement due to a ConocoPhillips breach termination event and following October 18, 2020 and on or before the date of any such termination, a ConocoPhillips competing proposal was announced, disclosed or otherwise communicated to the ConocoPhillips board and not withdrawn without qualification at least seven business days prior to the date of such termination (however, with respect to the preceding clauses (i)(A) and (i)(B), a ConocoPhillips competing proposal will not be deemed to have been "publicly withdrawn" by any person if, within 12 months of the termination of the merger agreement, ConocoPhillips or any of its subsidiaries have entered into a definitive agreement with respect to, or have consummated, or have approved or recommended to the ConocoPhillips stockholders or otherwise not opposed, in the case of a tender offer or exchange offer, a ConocoPhillips competing proposal made by or on behalf of such person or any of its affiliates), and (ii) within 12 months after the date of such termination, ConocoPhillips enters into a definitive agreement with respect to a ConocoPhillips competing proposal (or publicly approves or recommends to the ConocoPhillips stockholders or otherwise does not oppose, in the case of a tender or exchange offer, a ConocoPhillips competing proposal) or consummates a ConocoPhillips competing proposal. For purposes of this paragraph, any reference in the definition of ConocoPhillips competing proposal to "20%" will be deemed to be a reference to "50%" (other than with respect to any ConocoPhillips competing proposal by any person (or its affiliates) that has made a ConocoPhillips competing proposal meeting the requirements of the preceding clause (i)(A) or (i)(B)) and any ConocoPhillips competing proposal made prior to October 18, 2020 will be deemed to have been made following October 18, 2020 if ConocoPhillips breaches the "no solicitation" obligations described above and in the section entitled "The Merger Agreement—No Solicitation; Changes of Recommendation—No Solicitation by ConocoPhillips" beginning on page 155 with respect to such ConocoPhillips competing proposal.

        In no event will ConocoPhillips be required to pay the reverse termination fee on more than one occasion.

        The merger agreement also requires ConocoPhillips to pay Concho an expense reimbursement fee of $142.5 million (which we refer to as the "Concho expense reimbursement") in the event either ConocoPhillips or Concho terminates the merger agreement due to a ConocoPhillips stockholder approval termination event.

Termination Fees Payable by Concho

        The merger agreement requires Concho to pay ConocoPhillips a termination fee of $300 million (which we refer to as the "termination fee") if:

•

ConocoPhillips terminates the merger agreement due to a Concho recommendation change or due to a Concho no solicitation breach termination event; or

•

(i) (A) ConocoPhillips or Concho terminates the merger agreement due to a Concho stockholder approval termination event and on or before the date of any such termination, a Concho competing proposal was publicly announced or publicly disclosed and was not publicly withdrawn without qualification at least seven business days prior to the Concho special meeting or (B) Concho or ConocoPhillips terminates the merger agreement due to an end date termination event or ConocoPhillips terminates the merger agreement due to a Concho breach termination event and following October 18, 2020 and on or before the date of any such termination, a Concho competing proposal has been announced, disclosed or otherwise communicated to the Concho board and not withdrawn without qualification at least seven business days prior to the date of such termination (however, with respect to the preceding clauses (i)(A) and (i)(B), a Concho competing proposal will not be deemed to have been "publicly withdrawn" by any person if, within 12 months of the termination of the merger agreement, Concho or any of its subsidiaries have entered into a definitive agreement with respect to, or have consummated, or have approved or recommended to the Concho stockholders or otherwise have not opposed, in the case of a tender offer or exchange offer, a Concho competing proposal made by or on behalf of such person or any of its affiliates), and (ii) within 12 months after the date of such termination, Concho enters into a definitive agreement with respect to a Concho competing proposal (or publicly approves or recommends to the Concho stockholders or otherwise does not oppose, in the case of a tender or exchange offer, a Concho competing proposal) or consummates a Concho competing proposal. For purposes of this paragraph, any reference in the definition of Concho competing proposal to "20%" will be deemed to be a reference to "50%" (other than with respect to any Concho competing proposal by any person (or its affiliates) that has made a Concho competing proposal meeting the requirements of the preceding clause (i)(A) or (i)(B)) and any Concho competing proposal made prior to October 18, 2020 will be deemed to have been made following October 18, 2020 if Concho breaches the "no solicitation" obligations described above and in the section entitled "The Merger Agreement—No Solicitation; Changes of Recommendation—No Solicitation by Concho" beginning on page 157 with respect to such Concho competing proposal.

        In no event will Concho be required to pay the termination fee on more than one occasion.

        The merger agreement also requires Concho to pay ConocoPhillips an expense reimbursement fee of $95 million (which we refer to as the "ConocoPhillips expense reimbursement") in the event either ConocoPhillips or Concho terminates the merger agreement due to a Concho stockholder approval termination event.

Regulatory Approvals (page 130)

        The completion of the merger is subject to the receipt of antitrust clearance in the United States. Under the HSR Act, and the rules promulgated thereunder, the merger may not be completed until notification and report forms have been filed with the Federal Trade Commission (which we refer to as the "FTC") and the Department of Justice (which we refer to as the "DOJ") and the applicable waiting period (or any extension of such waiting period) has expired or been terminated.

        On October 30, 2020, notification and report forms under the HSR Act were filed by each of ConocoPhillips and Concho with the FTC and the DOJ with respect to the merger. The waiting period with respect to the notification and report forms under the HSR Act expired at 11:59 p.m. Eastern Time on November 30, 2020.

        Neither ConocoPhillips nor Concho is aware of any material governmental approvals or actions that are required for completion of the merger other than as described above. It is presently contemplated that if any such additional material governmental approvals or actions are required, those approvals or actions will be sought.

        For additional information, see the section entitled "The Merger Agreement—HSR and Other Regulatory Approvals" beginning on page 171.

Specific Performance; Remedies (page 184)

        ConocoPhillips, Concho and Merger Sub have agreed that each will be entitled to an injunction or injunctions, or any other appropriate form of specific performance or equitable relief, to prevent breaches of the merger agreement and to enforce specifically the terms and provisions of the merger agreement.

        Except in the case of fraud or a willful and material breach, the monetary remedies and the specific performance remedies set forth in the merger agreement will be the receiving party's sole and exclusive remedy against the paying party.

No Appraisal Rights (page 218)

        No appraisal rights will be available with respect to the transactions contemplated by the merger agreement.

Material U.S. Federal Income Tax Consequences of the Merger (page 186)

        Concho and ConocoPhillips intend for the merger to qualify as a "reorganization" within the meaning of Section 368(a) of the Code. It is expected that U.S. holders (as defined in the section entitled "Material U.S. Federal Income Tax Consequences of the Merger") of shares of Concho common stock generally will not recognize any gain or loss for U.S. federal income tax purposes upon receipt of ConocoPhillips common stock in exchange for Concho 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 ConocoPhillips common stock. The completion of the merger is not conditioned on the merger qualifying for the intended tax treatment or upon the receipt of an opinion of counsel or IRS ruling to that effect.

        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 186. The discussion of the material U.S. federal income tax consequences contained in this joint 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 AS A RESULT OF THE MERGER TO YOU IN YOUR PARTICULAR CIRCUMSTANCES.

Litigation Relating to the Merger (page 139)

        As of December 9, 2020, four lawsuits have been filed in the United States District Court for the District of Delaware and one lawsuit has been filed in the United States District Court for the Eastern District of New York, each in connection with the merger. On November 23, 2020, a purported Concho stockholder filed a complaint naming Concho and the members of the Concho board of directors as defendants. On the same day, a second purported Concho stockholder filed a complaint naming Concho, the members of the Concho board of directors, ConocoPhillips and Merger Sub as defendants. On December 1, 2020, a purported ConocoPhillips stockholder filed a complaint naming ConocoPhillips and the members of the ConocoPhillips board of directors as defendants. On December 4, 2020, a purported Concho stockholder filed a complaint naming Concho and the members

of the Concho board of directors as defendants. On December 9, 2020, a purported ConocoPhillips stockholder filed a complaint naming ConocoPhillips and the members of the ConocoPhillips board of directors as defendants. The complaints allege, among other things, that the registration statement on Form S-4 filed by ConocoPhillips on November 18, 2020 relating to the merger fails to disclose certain allegedly material information concerning the transactions contemplated by the merger agreement 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 transactions contemplated by the merger agreement. Each of ConocoPhillips and Concho believes that the allegations in the complaints are without merit. Additional lawsuits arising out of the merger may also be filed in the future.

        For additional information, see the section entitled "Litigation Relating to the Merger" beginning on page 139.

Comparison of Stockholders' Rights (page 205)

        The rights of Concho stockholders who receive shares of ConocoPhillips common stock in the merger will be governed by the Amended and Restated Certificate of Incorporation of ConocoPhillips (which we refer to as the "ConocoPhillips certificate of incorporation") and the Amended and Restated By-Laws of ConocoPhillips (which we refer to as the "ConocoPhillips bylaws"), rather than by the Restated Certificate of Incorporation of Concho (which we refer to as the "Concho certificate of incorporation") and the Fifth Amended and Restated Bylaws of Concho (which we refer to as the "Concho bylaws"). As a result, Concho stockholders will have different rights once they become ConocoPhillips stockholders due to the differences in the organizational documents of Concho and ConocoPhillips. The key differences are described in the section entitled "Comparison of Stockholders' Rights" beginning on page 205.

Listing of ConocoPhillips Common Stock; Delisting and Deregistration of Concho Shares (page 138)

        If the merger is completed, the shares of ConocoPhillips common stock to be issued in the merger will be listed for trading on the NYSE, shares of Concho common stock will be delisted from the NYSE and deregistered under the Exchange Act, and Concho will no longer be required to file periodic reports with the SEC pursuant to the Exchange Act.

SELECTED HISTORICAL CONSOLIDATED FINANCIAL DATA OF CONOCOPHILLIPS

        The following table presents selected historical consolidated financial data for the periods indicated. The selected historical consolidated financial data as of and for the years ended December 31, 2019, and 2018 and for the year ended December 31, 2017, is derived from ConocoPhillips' audited consolidated financial statements and related notes thereto included in its Annual Report on Form 10-K for the fiscal year ended December 31, 2019, which is incorporated by reference into this joint proxy statement/prospectus. The selected historical consolidated financial data for the nine months ended September 30, 2020, and 2019, and as of September 30, 2020, is derived from ConocoPhillips' unaudited interim consolidated financial statements and related notes thereto contained in its Quarterly Report on Form 10-Q for the quarter ended September 30, 2020, which is incorporated by reference into this joint proxy statement/prospectus.

        The selected historical consolidated financial data as of December 31, 2017, 2016 and 2015, and for the years ended December 31, 2016 and 2015, is derived from ConocoPhillips' audited consolidated financial statements and related notes thereto for such years, which have not been included or incorporated by reference into this joint proxy statement/prospectus. The selected historical consolidated financial data as of September 30, 2019, is derived from ConocoPhillips' unaudited interim consolidated financial statements and related notes thereto contained in its Quarterly Report on Form 10-Q for the quarter ended September 30, 2019, which has not been included or incorporated by reference into this joint proxy statement/prospectus.

        In presenting the selected historical consolidated financial data in conformity with GAAP, ConocoPhillips is required to make estimates and assumptions that affect the amounts reported. See "Management's Discussion and Analysis of Financial Condition and Results of Operations," included in its Annual Report on Form 10-K for the fiscal year ended December 31, 2019, and its Quarterly Report on Form 10-Q for the quarter ended September 30, 2020, which are incorporated by reference into this joint proxy statement/prospectus, for a detailed discussion of the accounting policies that ConocoPhillips believes require subjective and complex judgments that could potentially affect reported results. The unaudited financial statements as of and for the periods described above have been prepared on the same basis as the audited consolidated financial statements incorporated by reference in this joint proxy statement/prospectus and include all normal and recurring adjustments necessary for a fair statement of the information for the periods presented.

        The selected historical consolidated financial data is only a summary and is not necessarily indicative of the future performance of ConocoPhillips, nor does it include the effects of the merger discussed in this joint proxy statement/prospectus. Factors that impact the comparability of the selected historical consolidated financial data is also noted in the following table. This summary should be read together with other information contained in "Management's Discussion and Analysis of Financial Condition and Results of Operations," and the consolidated financial statements and related notes of ConocoPhillips included in its Annual Report on Form 10-K for the fiscal year ended December 31, 2019 and its Quarterly Report on Form 10-Q for the quarter ended September 30, 2020, which are

incorporated by reference into this joint proxy statement/prospectus. For additional information, see the section entitled "Where You Can Find More Information."

        In the nine-month period ended September 30, 2020, we disposed of our Australia-West assets for proceeds of $765 million, as well as our Niobrara interests for proceeds of approximately $359 million after customary adjustments. We also recognized a $1.3 billion after-tax unrealized loss on our CVE common shares in the nine-month period ended September 30, 2020, as compared to a $0.5 billion after-tax gain on those shares in the nine-month period of 2019.

        In 2019, we disposed of two ConocoPhillips U.K. subsidiaries for proceeds of $2.2 billion after interest and customary adjustments.

        In 2017, we disposed of assets for consideration of approximately $16 billion, including our 50 percent nonoperated interest in the FCCL Partnership, as well as the majority of our western Canada gas assets, and our interests in the San Juan Basin.

SELECTED HISTORICAL CONSOLIDATED FINANCIAL DATA OF CONCHO

        The following table presents selected historical consolidated financial data for Concho (i) as of and for the years ended December 31, 2019, 2018, 2017, 2016 and 2015 and (ii) as of and for the nine months ended September 30, 2020 and 2019. The consolidated financial data for each of the years ended December 31, 2019, 2018 and 2017, and as of December 31, 2019 and 2018 have been derived from Concho's selected financial data and audited consolidated financial statements included in its Annual Report on Form 10-K for the fiscal year ended December 31, 2019, which is incorporated by reference herein in its entirety. The selected historical consolidated financial data of Concho for each of the years ended December 31, 2016 and 2015 and as of December 31, 2017, 2016 and 2015 have been derived from Concho's selected financial data and audited consolidated financial statements for such years, which have not been incorporated by reference herein. The selected historical consolidated financial data for the nine months ended September 30, 2020 and 2019 and as of September 30, 2020 have been derived from Concho's unaudited consolidated financial data included in its Quarterly Report on Form 10-Q for the quarter ended September 30, 2020, which is incorporated by reference herein in its entirety. This selected balance sheet data as of September 30, 2019 has been derived from Concho's unaudited consolidated financial statements as of September 30, 2019, which have not been incorporated by reference herein.

        The information set forth below is only a summary and is not necessarily indicative of the results of future operations of Concho nor does it include the effects of the merger. This summary should be read together with the consolidated financial statements, the related notes and the sections entitled "Management's Discussion and Analysis of Financial Condition and Results of Operations" in Concho's Annual Report on Form 10-K for the fiscal year ended December 31, 2019 and Quarterly Report on Form 10-Q for the quarter ended September 30, 2020, each of which is incorporated by reference

herein in its entirety. For additional information, see the section titled "Where You Can Find More Information."

SUMMARY UNAUDITED PRO FORMA COMBINED FINANCIAL DATA

        The following summary unaudited pro forma combined income statement data for the nine months ended September 30, 2020, and for the year ended December 31, 2019, are presented as if the merger had occurred on January 1, 2019. The summary unaudited pro forma combined balance sheet data is presented as if the merger had occurred on September 30, 2020. The following summary unaudited pro forma combined financial data has been prepared for illustrative purposes only, reflects transaction-related pro forma adjustments, based on available information and certain assumptions that ConocoPhillips believes are reasonable, and is not necessarily indicative of what the combined company's financial condition or results of operations would have been had the merger occurred as of the dates indicated. In addition, the unaudited pro forma combined financial data does not purport to project the future financial condition or results of operations of the combined company.

        Future results may vary significantly from the results reflected because of various factors, including those discussed in the section entitled "Risk Factors" beginning on page 41. The following summary unaudited pro forma combined financial data should be read in conjunction with the section titled "Unaudited Pro Forma Combined Financial Statements" and the related notes thereto included in this joint proxy statement/prospectus.

SUMMARY PRO FORMA COMBINED PROVED RESERVES AND PRODUCTION DATA

        The following tables present the estimated pro forma combined net proved developed and undeveloped reserves as of December 31, 2019, giving effect to the merger as if it had been completed on December 31, 2019. The pro forma production data set forth below gives effect to the merger as if it had been completed on January 1, 2019.

        The following summary pro forma proved reserves and production data has been prepared for illustrative purposes only and is not intended to be a projection of future results of the combined company. Future results may vary significantly from the results reflected because of various factors, including those discussed in the section entitled "Risk Factors" beginning on page 41. The summary pro forma proved reserves and production data should be read in conjunction with the section titled "Unaudited Pro Forma Combined Financial Statements" and the related notes thereto included in this joint proxy statement/prospectus.