SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
SCHEDULE 13D
Under the Securities Exchange Act of 1934
Amendment No. 4
Pioneer Natural Resources Company
________________________________________________________
(Name of Issuer)
Common Stock
_______________________________________________________
(Title of Class and Securities)
723787107
_______________________________________________________
(CUSIP Number of Class of Securities)
O. Mason Hawkins
Chairman of the Board and C.E.O.
and
Andrew R. McCarroll
Vice President & General Counsel
Southeastern Asset Management, Inc.
6410 Poplar Avenue, Suite 900
Memphis, TN 38119
(901) 761-2474
___________________________________________________________
(Name, Address and Telephone Number of Person Authorized to
Receive Notices and Communications)
September 24, 2010
___________________________________________
(Date of Event which Requires
Filing of this Statement)
If the filing person has previously filed a statement on Schedule 13G to report
the acquisition which is the subject of this Schedule 13D, and is filing this
Schedule because of Sections 240.13d-1(e), 240.13d-1(f), or 240.13d-1(g), check
the following box: [X]
CUSIP No. 723787107 13D
_____________________________________________________________________________
(1) NAMES OF REPORTING PERSONS
Southeastern Asset Management, Inc. I.D. No. 62-0951781
_____________________________________________________________________________
(2) CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP:
(a)
(b) X
_____________________________________________________________________________
(3) SEC USE ONLY
_____________________________________________________________________________
(4) SOURCE OF FUNDS
00: Funds of investment advisory clients
_____________________________________________________________________________
(5) CHECK BOX IF DISCOSURE OF LEGAL PROCEEDINGS IS
REQUIRED PURSUANT TO ITEMS 2(d) or 2(e) [ ]
_____________________________________________________________________________
(6) CITIZENSHIP OR PLACE OF ORGANIZATION
Tennessee
_____________________________________________________________________________
:(7) SOLE VOTING POWER
: (Discretionary Accounts)
NUMBER OF SHARES BENEFICIALLY : 4,718,791 shares
OWNED BY EACH REPORTING PERSON __________________________________________
WITH :(8) SHARED OR NO VOTING POWER
: 9,478,900 shares (Shared)
: 1,451,800 shares (No Vote)
__________________________________________
:(9) SOLE DISPOSITIVE POWER
(Discretionary Accounts)
: 6,170,591 shares
__________________________________________
:(10) SHARED DISPOSITIVE POWER
: 9,478,900 shares (Shared)
: 0 shares (None)
_____________________________________________________________________________
(11) AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
15,649,491 shares
_____________________________________________________________________________
(12) CHECK BOX IF THE AGGREGATE AMOUNT IN ROW 11 EXCLUDES
CERTAIN SHARES
_____________________________________________________________________________
(13) PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 11
13.5 %
_____________________________________________________________________________
(14) TYPE OF REPORTING PERSON
IA
_____________________________________________________________________________
CUSIP No. 723787107 13D
_____________________________________________________________________________
(1) NAMES OF REPORTING PERSONS
Longleaf Partners Fund I.D. No. 63-6147721
_____________________________________________________________________________
(2) CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP:
(a)
(b) X
_____________________________________________________________________________
(3) SEC USE ONLY
_____________________________________________________________________________
(4) SOURCE OF FUNDS
00: Funds of investment company shareholders
_____________________________________________________________________________
(5) CHECK BOX IF DISCLOSURE OF LEGAL PROCEDDINGS IS
REQUIRED PURSUANT TO ITEMS 2(d) or 29e) [ ]
_____________________________________________________________________________
(6) CITIZENSHIP OR PLACE OF ORGANIZATION
Massachusetts
_____________________________________________________________________________
:(7) SOLE VOTING POWER
NUMBER OF SHARES BENEFICIALLY : None
OWNED BY EACH REPORTING PERSON __________________________________________
WITH :(8) SHARED VOTING POWER
: 7,133,900 shares (Shared)
__________________________________________
:(9) SOLE DISPOSITIVE POWER
: None
__________________________________________
:(10) SHARED DISPOSITIVE POWER
: 7,133,900 shares (Shared)
_____________________________________________________________________________
(11) AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
7,133,900 shares
_____________________________________________________________________________
(12) CHECK BOX IF THE AGGREGATE AMOUNT IN ROW 11 EXCLUDES
CERTAIN SHARES
_____________________________________________________________________________
(13) PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 11
6.2 %
_____________________________________________________________________________
(14) TYPE OF REPORTING PERSON
IV
_____________________________________________________________________________
CUSIP No. 723787107 13D
_____________________________________________________________________________
(1) NAMES OF REPORTING PERSONS
O. Mason Hawkins I.D. No. XXX-XX-XXXX
_____________________________________________________________________________
(2) CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP:
(a)
(b) X
_____________________________________________________________________________
(3) SEC USE ONLY
_____________________________________________________________________________
(4) SOURCE OF FUNDS
00: None
_____________________________________________________________________________
(5) CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS
REQUIRED PURSUANT TO ITEMS 2(d) or 2(e) [ ]
_____________________________________________________________________________
(6) CITIZENSHIP OR PLACE OF ORGANIZATION
Citizen of United States
_____________________________________________________________________________
:(7) SOLE VOTING POWER
: (Discretionary Accounts)
NUMBER OF SHARES BENEFICIALLY : None
OWNED BY EACH REPORTING PERSON __________________________________________
WITH :(8) SHARED VOTING POWER
: None
__________________________________________
:(9) SOLE DISPOSITIVE POWER
: None
__________________________________________
:(10) SHARED DISPOSITIVE POWER
: None
_____________________________________________________________________________
(11) AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
None (See Item 3)
_____________________________________________________________________________
(12) CHECK BOX IF THE AGGREGATE AMOUNT IN ROW 11 EXCLUDES
CERTAIN SHARES [ ]
_____________________________________________________________________________
(13) PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 11
0.0 %
_____________________________________________________________________________
(14) TYPE OF REPORTING PERSON
IN
_____________________________________________________________________________
Item 5. Interest In Securities Of The Issuer
Item 5 shall be amended and restated as follows:
(a) The aggregate number and percentage of Securities to which this
Schedule 13D relates is 15,649,491 shares of the common stock of the Issuer,
constituting approximately 13.5% of the 115,994,034 shares outstanding.
Common % of outstanding
Shares Common Shares
Held
___________________________________________________________________
Voting Authority
Sole: 4,718,791 4.1%
Shared: 9,478,900* 8.2%
None: 1,451,800 1.2%
Total 15,649,491 13.5%
*Consists of shares owned by Longleaf Partners Fund and Longleaf Partners
Small-Cap Fund, each a series of Longleaf Partners Funds Trust, an open-end
management investment company registered under the Investment Company Act of
1940.
Dispositive Authority
Sole: 6,170,591 5.3%
Shared: 9,478,900* 8.2%
None: 0 0.0%
Total 15,649,491 13.5%
*Consists of shares owned by Longleaf Partners Fund and Longleaf Partners
Small-Cap Fund, each a series of Longleaf Partners Funds Trust, an open-end
management investment company registered under the Investment Company Act of
1940.
(b) Southeastern generally has the sole power to dispose of or to
direct the disposition of the Securities held for discretionary accounts of its
investment clients, and may be granted the sole power to vote or direct the
vote of such Securities; such powers may be retained by or shared with the
respective clients for shared or non-discretionary accounts. Shares held by
any Series of Longleaf Partners Funds Trust are reported in the "shared"
category.
(c) Purchase or sale transactions in the Securities during the past
sixty days are disclosed on Schedule II.
(d) The investment advisory clients of Southeastern have the sole
right to receive and, subject to notice, to withdraw the proceeds from the sale
of the Securities, and the sole power to direct the receipt of dividends from
any of the Securities held for their respective accounts. Such clients may
also terminate the investment advisory agreements without penalty upon
appropriate notice. Southeastern does not have an economic interest in any of
the Securities reported herein.
(e) Not applicable.
Signatures
After reasonable inquiry and to the best of my knowledge and belief, I certify
that the information set forth in this statement is true, complete and correct.
Dated: September 27, 2010
Southeastern Asset Management, Inc.
By /s/ Andrew R. McCarroll
_______________________________________________
Andrew R. McCarroll
Vice President and General Counsel
Longleaf Partners Fund
By: Southeastern Asset Management, Inc.
/s/ Andrew R. McCarroll
_______________________________________________
Andrew R. McCarroll
Vice President & General Counsel
O. Mason Hawkins, Individually
/s/ O. Mason Hawkins
_______________________________________________
Joint Filing Agreement
In accordance with Rule 13d-1(k) 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 Amendment No. 4 to Schedule 13D with
respect to the Securities of the Issuer and further agree that this joint
filing agreement be included as an exhibit to this Amendment No. 4 to Schedule
13D. In evidence thereof, the undersigned hereby execute this Agreement as
of September 27, 2010.
Southeastern Asset Management, Inc.
By /s/ Andrew R. McCarroll
_______________________________________________
Andrew R. McCarroll
Vice President and General Counsel
Longleaf Partners Fund
By: Southeastern Asset Management, Inc.
/s/ Andrew R. McCarroll
_______________________________________________
Andrew R. McCarroll
Vice President & General Counsel
O. Mason Hawkins, Individually
/s/ O. Mason Hawkins
_______________________________________________
Schedule II
Transactions in the Last Sixty Days
Transaction Type Date # of Shares Price per Share *
Sale 07/28/2010 18,600 $59.90
Sale 08/02/2010 8,000 $60.89
Sale 08/02/2010 11,000 $60.89
Sale 08/02/2010 13,000 $60.89
Sale 08/02/2010 20,000 $60.89
Sale 08/02/2010 9,000 $60.89
Sale 08/04/2010 31,000 $61.21
Sale 08/04/2010 13,000 $61.21
Sale 08/04/2010 16,000 $61.21
Sale 08/04/2010 55,000 $61.21
Sale 08/27/2010 20,000 $58.68
Sale 08/27/2010 1,000 $58.68
Sale 09/02/2010 1,700 $61.01
Sale 09/07/2010 134,000 $61.89
Sale 09/13/2010 103,200 $65.01
Sale 09/13/2010 33,800 $65.01
Sale 09/23/2010 68,000 $66.46
Sale 09/24/2010 3,000 $64.00
Sale 09/24/2010 2,000 $64.00
Sale 09/24/2010 62,000 $64.00
Sale 09/24/2010 18,000 $64.00
Sale 09/24/2010 15,000 $64.00
Sale 09/24/2010 13,000 $64.00
Sale 09/24/2010 300 $64.00
Sale 09/24/2010 700 $64.00
Sale 09/24/2010 7,000 $64.00
Sale 09/24/2010 28,000 $64.00
Sale 09/24/2010 8,800 $64.00
Sale 09/24/2010 142,200 $64.00
Sale 09/24/2010 7,000 $64.00
Sale 09/24/2010 8,000 $64.00
Sale 09/24/2010 8,000 $64.00
Sale 09/24/2010 6,000 $64.00
Sale 09/24/2010 23,000 $64.00
Sale 09/24/2010 34,000 $64.00
Sale 09/24/2010 9,000 $64.00
Sale 09/24/2010 16,000 $64.00
Sale 09/24/2010 56,000 $64.00
Sale 09/24/2010 23,000 $64.00
Sale 09/24/2010 61,000 $64.00
Sale 09/24/2010 7,000 $64.00
Sale 09/24/2010 18,000 $64.00
Sale 09/24/2010 500 $64.00
Sale 09/24/2010 4,000 $64.00
Sale 09/24/2010 100 $64.00
Sale 09/24/2010 5,000 $64.00
Sale 09/24/2010 100 $64.00
Sale 09/24/2010 1,600 $64.00
Sale 09/24/2010 2,000 $64.00
Sale 09/24/2010 1,000 $64.00
Sale 09/24/2010 1,700 $64.00
Sale 09/24/2010 15,000 $64.00
Sale 09/24/2010 113,000 $64.00
Sale 09/24/2010 109,000 $64.00
Sale 09/24/2010 7,000 $64.00
Sale 09/24/2010 1,000 $64.00
Sale 09/24/2010 9,000 $64.00
Sale 09/24/2010 2,000 $64.00
Sale 09/24/2010 42,000 $64.00
Sale 09/24/2010 5,000 $64.00
Sale 09/24/2010 6,000 $64.00
Sale 09/24/2010 2,000 $64.00
Sale 09/24/2010 10,000 $64.00
Sale 09/24/2010 19,000 $64.00
Sale 09/24/2010 11,000 $64.00
Sale 09/24/2010 21,500 $64.00
Sale 09/24/2010 18,500 $64.00
Sale 09/24/2010 7,000 $64.00
Sale 09/24/2010 4,000 $64.00
Sale 09/24/2010 6,000 $64.00
Sale 09/24/2010 5,000 $64.00
Sale 09/24/2010 3,000 $64.00
Sale 09/24/2010 18,000 $64.00
Sale 09/24/2010 13,000 $64.00
Sale 09/24/2010 16,800 $64.00
Sale 09/24/2010 32,068 $64.00
Sale 09/24/2010 50,000 $64.00
Sale 09/24/2010 10,000 $64.00
Sale 09/24/2010 884,000 $64.00
Sale 09/24/2010 4,800 $64.00
Sale 09/24/2010 27,600 $64.00
Sale 09/24/2010 340,000 $64.00
Sale 09/24/2010 158,732 $64.00
Sale 09/24/2010 134,000 $64.00
Sale 09/24/2010 227,700 $64.00
Sale 09/24/2010 4,000 $64.00
Sale 09/24/2010 32,000 $64.00
Sale 09/24/2010 14,700 $64.00
Sale 09/24/2010 21,600 $64.00
Sale 09/24/2010 80,900 $64.00
Sale 09/24/2010 100,000 $64.00
Sale 09/24/2010 24,400 $64.00
Sale 09/24/2010 232,300 $64.00
Sale 09/24/2010 4,000 $64.00
Sale 09/24/2010 214,400 $64.00
Sale 09/24/2010 1,000 $64.00
Sale 09/24/2010 12,000 $64.00
Sale 09/24/2010 22,000 $64.00
Sale 09/24/2010 18,000 $64.00
Sale 09/24/2010 1,000 $64.00
Sale 09/24/2010 35,000 $64.00
Sale 09/24/2010 3,000 $64.00
Sale 09/24/2010 4,000 $64.00
Sale 09/24/2010 11,000 $64.00
Sale 09/24/2010 15,000 $64.00
Sale 09/24/2010 14,000 $64.00
Sale 09/24/2010 3,000 $64.00
Sale 09/24/2010 7,000 $64.00
Sale 09/24/2010 6,000 $64.00
Sale 09/24/2010 10,000 $64.00
Sale 09/24/2010 4,000 $64.00
Sale 09/24/2010 3,000 $64.00
Sale 09/24/2010 1,000 $64.00
Sale 09/24/2010 23,000 $64.00
Sale 09/24/2010 3,000 $64.00
Sale 09/24/2010 1,000 $64.00
Sale 09/24/2010 28,000 $64.00
Sale 09/24/2010 4,000 $64.00
Sale 09/24/2010 1,000 $64.00
Sale 09/24/2010 3,000 $64.00
Sale 09/24/2010 3,000 $64.00
Sale 09/24/2010 23,000 $64.00
Sale 09/24/2010 6,000 $64.00
Sale 09/24/2010 1,200 $64.00
Sale 09/24/2010 3,800 $64.00
Sale 09/24/2010 5,000 $64.00
Sale 09/24/2010 37,000 $64.00
Sale 09/24/2010 18,000 $64.00
Sale 09/24/2010 2,000 $64.00
Sale 09/24/2010 4,000 $64.00
Sale 09/24/2010 7,500 $64.00
Sale 09/24/2010 2,000 $64.00
Sale 09/24/2010 1,000 $64.00
Sale 09/24/2010 4,500 $64.00
Sales by Southeastern's clients were made in the ordinary course of
business through brokers and were primarily a result of the need to
rebalance portfolios following an increase in the Issuer's stock price.
Sales as a result of this rebalancing are now complete. While facts
and circumstances may change, and Southeastern retains flexibility
to make additional purchases and/or sales, no further sales are
anticipated at this time. In addition to the above transactions, on
September 7, 2010, clients of Southeastern terminating their
advisory relationship removed 80,000 shares from Southeastern's
discretion.
* Net of commissions
1
SCHEDULE 13D - Pioneer Natural Resources Company ("Issuer")
2