SECURITIES AND EXCHANGE COMMISSION
                      Washington, D.C.  20549
                            SCHEDULE 13G
             Under the Securities Exchange Act of 1934
                         (Initial Filing)*
                 Pioneer Natural Resources Company
             ------------------------------------------
                          (Name of Issuer)
                            Common Stock
            -------------------------------------------
                  (Title of Class and Securities)
                             723787107
             --------------------------------------------
               (CUSIP Number of Class of Securities)
* The remainder of this cover page shall be filled out for a
reporting person's initial filing on this form with respect to the
subject class of securities, and for any subsequent amendment
containing information which would alter the disclosures provided
in a prior page.
The information required in the remainder of this cover page shall
not be deemed to be "filed" for the purpose of Section 18 of the
Securities Exchange Act of 1934 ("Act") or otherwise subject to the
liabilities of that section of the Act but shall be subject to all
other provisions of the Act (however, see the Notes).
                  (Continued on following page(s))
CUSIP No. 723787107                                    13G
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(1)  NAMES OF REPORTING PERSONS
     Southeastern Asset Management, Inc.      I.D. No. 62-0951781
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(2)  CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP:
                                              (a)
                                              (b) X
- -------------------------------------------------------------------
(3)  SEC USE ONLY
- -------------------------------------------------------------------
(4)  CITIZENSHIP OR PLACE OF ORGANIZATION
     Tennessee
- -------------------------------------------------------------------
                                   :(5) SOLE VOTING POWER
                                   :   (Discretionary Accounts)
NUMBER OF SHARES BENEFICIALLY      :    6,809,400 shares
OWNED BY EACH REPORTING PERSON     --------------------------------
WITH                               :(6) SHARED OR NO VOTING POWER
                                   :   5,277,900 shares (Shared)
                                       1,539,800 shares (No Vote)
                                   --------------------------------
                                   :(7) SOLE DISPOSITIVE POWER
                                        (Discretionary Accounts)
                                   :    8,310,200 shares
                                   --------------------------------
                                   :(8)  SHARED OR NO DISPOSITIVE
                                         POWER
                                   :   5,277,900 shares (Shared)
                                          39,000 SHARES (None)
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(9)  AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
      (Discretionary & Non-discretionary Accounts)
       13,627,100 shares
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(10)  CHECK BOX IF THE AGGREGATE AMOUNT IN ROW 9 EXCLUDES
      CERTAIN SHARES
- -------------------------------------------------------------------
(11)  PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9
      13.6%
- -------------------------------------------------------------------
(12)  TYPE OF REPORTING PERSON
      IA
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CUSIP No.  723787107                                    13G
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(1)  NAMES OF REPORTING PERSONS
     Longleaf Partners Fund                   I.D. No. 63-6147721
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(2)  CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP:
                                              (a)
                                              (b) X
- -------------------------------------------------------------------
(3)  SEC USE ONLY
- -------------------------------------------------------------------
(4)  CITIZENSHIP OR PLACE OF ORGANIZATION
     Massachusetts business trust
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                                   :(5) SOLE VOTING POWER
                                   :   (Discretionary Accounts)
NUMBER OF SHARES BENEFICIALLY      :     None
OWNED BY EACH REPORTING PERSON     --------------------------------
WITH                               :(6) SHARED VOTING POWER
                                   :   5,277,900 shares
                                   --------------------------------
                                   :(7) SOLE DISPOSITIVE POWER
                                   :   (Discretionary Accounts)
                                   :     None
                                   --------------------------------
                                   :(8)  SHARED DISPOSITIVE POWER
                                   :    5,277,900 shares
- -------------------------------------------------------------------
(9)  AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
        5,277,900 shares
- -------------------------------------------------------------------
(10)  CHECK BOX IF THE AGGREGATE AMOUNT IN ROW 9 EXCLUDES
      CERTAIN SHARES
- -------------------------------------------------------------------
(11)  PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9
       5.3 %
- -------------------------------------------------------------------
(12)  TYPE OF REPORTING PERSON
      IV
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CUSIP No. 723787107                                  13G
- -------------------------------------------------------------------
(1)  NAMES OF REPORTING PERSONS
     O. Mason Hawkins                         I.D. No. ###-##-####
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(2)  CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP:
                                              (a)
                                              (b) X
- -------------------------------------------------------------------
(3)  SEC USE ONLY
- -------------------------------------------------------------------
(4)  CITIZENSHIP OR PLACE OF ORGANIZATION
     Citizen of United States
- -------------------------------------------------------------------
                                   :(5) SOLE VOTING POWER
                                   :   (Discretionary Accounts)
NUMBER OF SHARES BENEFICIALLY      :    None
OWNED BY EACH REPORTING PERSON     --------------------------------
WITH                               :(6) SHARED VOTING POWER
                                   :    None
                                   --------------------------------
                                   :(7) SOLE DISPOSITIVE POWER
                                   :    None
                                   --------------------------------
                                   :(8) SHARED DISPOSITIVE POWER
                                   :    None
- -------------------------------------------------------------------
(9)  AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
       None  (See Item 3 )
- -------------------------------------------------------------------
(10)  CHECK BOX IF THE AGGREGATE AMOUNT IN ROW 9 EXCLUDES
      CERTAIN SHARES
- -------------------------------------------------------------------
(11)  PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9
      0.0%
- -------------------------------------------------------------------
(12)  TYPE OF REPORTING PERSON
      IN
- -------------------------------------------------------------------
Item 1.
     (a). Name of Issuer: Pioneer Natural Resources Company
           ("Issuer")
     (b). Address of Issuer's Principal Executive Offices:
          1400 Williams Square West
          5205 N. O'Connor Blvd.
          Irving, TX 75039
Item 2.
     (a) and (b). Names and Principal Business Addresses of
         Persons Filing:
         (1). Southeastern Asset Management, Inc.
              6410 Poplar Ave., Suite 900
              Memphis, TN 38119
         (2). Longleaf Partners Fund
              6410 Poplar Ave., Suite 900
              Memphis, TN 38119
         (3). Mr. O. Mason Hawkins
              Chairman of the Board and C.E.O.
              Southeastern Asset Management, Inc.
              6410 Poplar Ave. Suite 900
              Memphis, TN 38119
     (c). Citizenship:
          Southeastern Asset Management, Inc. - A Tennessee
            corporation
          Longleaf Partners Fund, a series of Longleaf
            Partners Funds Trust, a Massachusetts business
            trust
          Mr. O. Mason Hawkins - U.S. Citizen
     (d). Title of Class of Securities:  Common Stock, (the
            "Securities").
     (e). Cusip Number: 723787107
Item 3.  If this statement is filed pursuant to Rules 13d-1
 (b) or 13d-2 (b), check whether the person filing is a:
     (d). Investment Company registered under Sec. 8 of the
          Investment Company Act- Longleaf Partners Fund, a
          series of Longleaf Partners Funds Trust.
     (e). Investment Advisor registered under Section 203 of
          the Investment Advisers Act of 1940.  This
          statement is being filed by Southeastern Asset
          Management, Inc. as a registered investment
          adviser. All of the securities covered by this
          report are owned legally by Southeastern's
          investment advisory clients and none are owned
          directly or indirectly by Southeastern.  As
          permitted by Rule 13d-4, the filing of this
          statement shall not be construed as an admission
          that Southeastern Asset Management, Inc. is the
          beneficial owner of any of the securities covered
          by this statement.
     (g). Parent Holding Company.  This statement is also
          being filed by Mr. O. Mason Hawkins, Chairman of
          the Board and Chief Executive Officer of
          Southeastern Asset Management, Inc. in the event he
          could be deemed to be a controlling person of that
          firm as the result of his official positions with
          or ownership of its voting securities. The
          existence of such control is expressly disclaimed.
          Mr.  Hawkins does not own directly or indirectly
          any securities covered by this statement for his
          own account.  As permitted by Rule 13d-4, the
          filing of this statement shall not be construed as
          an admission that Mr. Hawkins is the beneficial
          owner of any of the securities covered by this
          statement.
Item 4. Ownership:
     (a). Amount Beneficially Owned: (At June 30, 2022)
          13,627,100 shares
     (b). Percent of Class:
           13.6%
          Above percentage is based on 100,444,593 shares of
          Common Stock outstanding at June 1, 1998, per
          information supplied by the Issuer.
          (c). Number of shares as to which such person has:
          (i).   sole power to vote or to direct the vote:
                  6,809,400 shares
          (ii).  shared or no power to vote or to direct the
                 vote:
                 Shared - 5,277,900 shares owned by Longleaf
                 Partners Fund, a series of Longleaf Partners
                 Funds Trust, an open-end management
                 investment company registered under the
                 Investment Company Act of 1940.
                 No Power to Vote - 1,539,800
          (iii). sole power to dispose or to direct the
                 disposition of:
                  8,310,200 shares
          (iv).  shared or no power to dispose or to direct
                 the disposition of:
                 Shared - 5,277,900 shares owned by Longleaf
                 Partners Fund, a series of Longleaf Partners
                 Funds Trust, an open-end management
                 investment company registered under the
                 Investment Company Act of 1940.
                 No Power - 39,000 shares
Item 5. Ownership of Five Percent or Less of a Class:  N/A
Item 6. Ownership of More Than Five Percent on Behalf of
        Another Person:  N/A
Item 7. Identification and Classification of the Subsidiary
        Which Acquired the Security Being Reported on By the
        Parent Holding Company:  N/A
Item 8. Identification and Classification of Members of the
        Group:  N/A
Item 9. Notice of Dissolution of Group:  N/A
Item 10. Certification:
By signing below I certify that, to the best of my knowledge
and belief, the securities referred to above were acquired in
the ordinary course of business and were not acquired for the
purpose and do not have the effect of changing or influencing
the control of the issuer of such securities and were not
acquired in connection with or as a participant in any
transaction having such purposes or effect.
                             Signatures
After reasonable inquiry and to the best of the knowledge and
belief of the undersigned, the undersigned certifies that the
information set forth in this statement is true, complete, and
correct.
Dated: July 8, 2022
Southeastern Asset                   Longleaf Partners Fund
Management, Inc.
By  /s/ Charles D. Reaves         By  /s/ Charles D.  Reaves
- ---------------------------       --------------------------
Charles D. Reaves                    Charles D. Reaves
Vice President and                   Executive Vice President
  General Counsel
O. Mason Hawkins, Individually
/s/ O. Mason Hawkins
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                       Joint Filing Agreement
In accordance with Rule 13d-1(f) under the Securities Exchange Act
of 1934, the persons or entities named below agree to the joint
filing on behalf of each of them of this Schedule 13G with respect
to the Securities of the Issuer and further agree that this joint
filing agreement be included as an exhibit to this Schedule 13G. In
evidence thereof, the undersigned hereby execute this Agreement as
of the 8th day of July, 1998.
Southeastern Asset                   Longleaf Partners Fund
Management, Inc.
By  /s/ Charles D. Reaves         By  /s/ Charles D.  Reaves
- ---------------------------       --------------------------
Charles D. Reaves                    Charles D. Reaves
Vice President and                   Executive Vice President
  General Counsel
O. Mason Hawkins, Individually
/s/ O. Mason Hawkins
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