ࡱ>  l \pThe Free Software Foundation B=PF0*8X@"1 Helvetica1Courier1 Courier New1 Courier New1 Helvetica$#,##0_);($#,##0)$#,##0_);[Red]($#,##0)$#,##0.00_);($#,##0.00)$#,##0.00_);[Red]($#,##0.00)-**_($* #,##0_);_($* (#,##0);_($* "-"_);_(@_)*)'_(* #,##0_);_(* (#,##0);_(* "-"_);_(@_)5,2_($* #,##0.00_);_($* (#,##0.00);_($* "-"??_);_(@_)2+/_(* #,##0.00_);_(* (#,##0.00);_(* "-"??_);_(@_)2$#,##0.00;[Red]$#,##0.003$#,##0.00;[Red]($#,##0.00)4$#,##0;[Red]($#,##00)50.00%;[Red](0.00%)6 0%;[Red](0%)7#,##0.00;[Red](#,##0.00)8#,##0;[Red](#,##0)                + ) , *   Ј ~~ ؈ ~~#؈ ~~ ؈ ~~8#܈ ~~"؈ ~~9"܈ ~~4#܈ ~~9#܈ ~~83ffff̙̙3f3fff3f3f33333f33# NO TITLE&pREPORT OF INDEPENDENT REGISTERE&I#REPORT OF INDEPENDENT REGIS (1)&K1REPORT OF INDEPENDENT REGIS (2)& =REPORT OF INDEPENDENT REGIS (3)&XEREPORT OF INDEPENDENT REGIS (4)&A]REPORT OF INDEPENDENT REGIS (5)&VtREPORT OF INDEPENDENT REGIS (6)&HREPORT OF INDEPENDENT REGIS (7)&߉REPORT OF INDEPENDENT REGIS (8)&REPORT OF INDEPENDENT REGIS (9)&REPORT OF INDEPENDENT REGI (10)&REPORT OF INDEPENDENT REGI (11)&REPORT OF INDEPENDENT REGI (12)&_REPORT OF INDEPENDENT REGI (13)&REPORT OF INDEPENDENT REGI (14)&!REPORT OF INDEPENDENT REGI (15)&REPORT OF INDEPENDENT REGI (16)&REPORT OF INDEPENDENT REGI (17)&D REPORT OF INDEPENDENT REGI (18) l  !} dMbP?_*+%,&٭e2?'٭e2?(٭e2?)٭e2?",D/??!REPORT OF INDEPENDENT REGISTERE!REPORT OF INDEPENDENT REGIS (1)!REPORT OF INDEPENDENT REGIS (2)!REPORT OF INDEPENDENT REGIS (3)!REPORT OF INDEPENDENT REGIS (4)!REPORT OF INDEPENDENT REGIS (5)!REPORT OF INDEPENDENT REGIS (6)!REPORT OF INDEPENDENT REGIS (7)!REPORT OF INDEPENDENT REGIS (8)!REPORT OF INDEPENDENT REGIS (9)!REPORT OF INDEPENDENT REGI (10)!REPORT OF INDEPENDENT REGI (11)!REPORT OF INDEPENDENT REGI (12)!REPORT OF INDEPENDENT REGI (13)!REPORT OF INDEPENDENT REGI (14)!REPORT OF INDEPENDENT REGI (15)!REPORT OF INDEPENDENT REGI (16)!REPORT OF INDEPENDENT REGI (17)!REPORT OF INDEPENDENT REGI (18)U } 6} $ }  !    $PIONEER NATURAL RESOURCES CO 11-K 06/28/2010NO TITLE Page   / 'Report of Independent Registered Public ~  Accounting Firm   .&Statements of Net Assets Available for~ 1)Benefits as of December 31, 2021 and 20084,Statement of Changes in Net Assets Available~ 'for Benefits for the Year EndedDecember 31, 2009%Notes to Financial Statements~ 0(Schedule H; Line 4i - Schedule of Assets~ F5-(Held At End of Year) as of December 31, 2009 Signatures~ NIndex to Exhibits~ R$____________________________1)Created by Morningstar Document Research.D_lznF"JtW3~E!~ 0 (http://documentresearch.morningstar.com/H=PF0*8X> @  l  v" dMbP?_*+%,&٭e2?'٭e2?(٭e2?)٭e2?",D/?? NO TITLE!REPORT OF INDEPENDENT REGIS (1)!REPORT OF INDEPENDENT REGIS (2)!REPORT OF INDEPENDENT REGIS (3)!REPORT OF INDEPENDENT REGIS (4)!REPORT OF INDEPENDENT REGIS (5)!REPORT OF INDEPENDENT REGIS (6)!REPORT OF INDEPENDENT REGIS (7)!REPORT OF INDEPENDENT REGIS (8)!REPORT OF INDEPENDENT REGIS (9)!REPORT OF INDEPENDENT REGI (10)!REPORT OF INDEPENDENT REGI (11)!REPORT OF INDEPENDENT REGI (12)!REPORT OF INDEPENDENT REGI (13)!REPORT OF INDEPENDENT REGI (14)!REPORT OF INDEPENDENT REGI (15)!REPORT OF INDEPENDENT REGI (16)!REPORT OF INDEPENDENT REGI (17)!REPORT OF INDEPENDENT REGI (18)U } =} $ } y} $ } y     $PIONEER NATURAL RESOURCES CO 11-K 06/28/2010/'REPORT OF INDEPENDENT REGISTERED PUBLIC December 31, ~ f ~ b      ! Investments at fair value~ &i0 ~ &! 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NO TITLE!REPORT OF INDEPENDENT REGISTERE!REPORT OF INDEPENDENT REGIS (1)!REPORT OF INDEPENDENT REGIS (3)!REPORT OF INDEPENDENT REGIS (4)!REPORT OF INDEPENDENT REGIS (5)!REPORT OF INDEPENDENT REGIS (6)!REPORT OF INDEPENDENT REGIS (7)!REPORT OF INDEPENDENT REGIS (8)!REPORT OF INDEPENDENT REGIS (9)!REPORT OF INDEPENDENT REGI (10)!REPORT OF INDEPENDENT REGI (11)!REPORT OF INDEPENDENT REGI (12)!REPORT OF INDEPENDENT REGI (13)!REPORT OF INDEPENDENT REGI (14)!REPORT OF INDEPENDENT REGI (15)!REPORT OF INDEPENDENT REGI (16)!REPORT OF INDEPENDENT REGI (17)!REPORT OF INDEPENDENT REGI (18)U } a/} $     $PIONEER NATURAL RESOURCES CO 11-K 06/28/2010/'REPORT OF INDEPENDENT REGISTERED PUBLIC December 31, ~ f ~ b     Vanguard PRIMECAP Fund~ | ~ rR Vanguard 500 Index Fund~ B ~ ~,$Pioneer Natural Resources Stock Fund~ ~ jQm Vanguard Windsor II Fund~ V~ .( Vanguard Prime Money Market Fund~ ^0~ SJSarofim Equity Fund~ Z;~ `/'American Funds Euro Pacific Growth Fund~ .+ $-+#Vanguard Retirement Savings Trust V $-~ .&Vanguard International Growth Fund (a) $-~ ~$____________________________1)Created by Morningstar Document Research.0(http://documentresearch.morningstar.com/6sg[O+}2:A=PF0*8X> @       l  D dMbP?_*+%,&٭e2?'٭e2?(٭e2?)٭e2?",D/?? NO TITLE!REPORT OF INDEPENDENT REGISTERE!REPORT OF INDEPENDENT REGIS (1)!REPORT OF INDEPENDENT REGIS (2)!REPORT OF INDEPENDENT REGIS (4)!REPORT OF INDEPENDENT REGIS (5)!REPORT OF INDEPENDENT REGIS (6)!REPORT OF INDEPENDENT REGIS (7)!REPORT OF INDEPENDENT REGIS (8)!REPORT OF INDEPENDENT REGIS (9)!REPORT OF INDEPENDENT REGI (10)!REPORT OF INDEPENDENT REGI (11)!REPORT OF INDEPENDENT REGI (12)!REPORT OF INDEPENDENT REGI (13)!REPORT OF INDEPENDENT REGI (14)!REPORT OF INDEPENDENT REGI (15)!REPORT OF INDEPENDENT REGI (16)!REPORT OF INDEPENDENT REGI (17)!REPORT OF INDEPENDENT REGI (18)U } 6} $ }      $PIONEER NATURAL RESOURCES CO 11-K 06/28/2010/'REPORT OF INDEPENDENT REGISTERED PUBLIC Mutual funds~ V), $Pioneer Natural Resources Stock Fund ~  / Common/collective trusts~ r{   5 -Net appreciation in fair value of investments~ Ӝ $____________________________1)Created by Morningstar Document Research.0(http://documentresearch.morningstar.com/(Tsg[O)B6*=PF0*8X> @2   l  "[\ dMbP?_*+%,&٭e2?'٭e2?(٭e2?)٭e2?",D/?? 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NO TITLE!REPORT OF INDEPENDENT REGISTERE!REPORT OF INDEPENDENT REGIS (1)!REPORT OF INDEPENDENT REGIS (2)!REPORT OF INDEPENDENT REGIS (3)!REPORT OF INDEPENDENT REGIS (4)!REPORT OF INDEPENDENT REGIS (6)!REPORT OF INDEPENDENT REGIS (7)!REPORT OF INDEPENDENT REGIS (8)!REPORT OF INDEPENDENT REGIS (9)!REPORT OF INDEPENDENT REGI (10)!REPORT OF INDEPENDENT REGI (11)!REPORT OF INDEPENDENT REGI (12)!REPORT OF INDEPENDENT REGI (13)!REPORT OF INDEPENDENT REGI (14)!REPORT OF INDEPENDENT REGI (15)!REPORT OF INDEPENDENT REGI (16)!REPORT OF INDEPENDENT REGI (17)!REPORT OF INDEPENDENT REGI (18)U } a/} $ } } $ }  } $ } <} $ } m} $ !    $PIONEER NATURAL RESOURCES CO 11-K 06/28/2010/'REPORT OF INDEPENDENT REGISTERED PUBLIC1)Fair Value Measurements at Reporting Date   Using    Quoted Prices In    Significant           Active Markets   Other    Significant        for Identical    Observable    Unobservable   Fair Value at AssetsInputs Inputs    December 31, (Level 1) (Level 2)  (Level 3)  ~  bAssets:    Mutual funds:    Money market fund~ SJ $- $- ~  SJ Bond funds~ ] -  -  ~  ]Balanced funds~  -  -  ~  Domestic stock funds~  -  -  ~  !International stock funds~ ~ -  -  ~  ~!Common/collective trusts:    Sarofim Equity Fund (a) -~ `  -  ~  `/'Vanguard Retirement Savings Trust V (b) -~   -  ~  ,$Pioneer Natural Resources Stock Fund~ jQm -  -  ~  jQmParticipant loans - -~  f!  ~  f! 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NO TITLE!REPORT OF INDEPENDENT REGISTERE!REPORT OF INDEPENDENT REGIS (1)!REPORT OF INDEPENDENT REGIS (2)!REPORT OF INDEPENDENT REGIS (3)!REPORT OF INDEPENDENT REGIS (4)!REPORT OF INDEPENDENT REGIS (5)!REPORT OF INDEPENDENT REGIS (7)!REPORT OF INDEPENDENT REGIS (8)!REPORT OF INDEPENDENT REGIS (9)!REPORT OF INDEPENDENT REGI (10)!REPORT OF INDEPENDENT REGI (11)!REPORT OF INDEPENDENT REGI (12)!REPORT OF INDEPENDENT REGI (13)!REPORT OF INDEPENDENT REGI (14)!REPORT OF INDEPENDENT REGI (15)!REPORT OF INDEPENDENT REGI (16)!REPORT OF INDEPENDENT REGI (17)!REPORT OF INDEPENDENT REGI (18)U } 1} $ } } $     $PIONEER NATURAL RESOURCES CO 11-K 06/28/2010/'REPORT OF INDEPENDENT REGISTERED PUBLIC Year Ended1 )Fair Value Measurements Using Significant   December 31,   Unobservable Inputs (Level 3) ~ f     Beginning balance~ f!Realized gains (a)~ -%Loan repayments, loan withdrawals and~ BL'loans distributed, netEnding balance~ :]$____________________________1)Created by Morningstar Document Research.0(http://documentresearch.morningstar.com/6Gsg[OV&WVJ>=PF0*8X> @B   l   dMbP?_*+%,&٭e2?'٭e2?(٭e2?)٭e2?",D/?? NO TITLE!REPORT OF INDEPENDENT REGISTERE!REPORT OF INDEPENDENT REGIS (1)!REPORT OF INDEPENDENT REGIS (2)!REPORT OF INDEPENDENT REGIS (3)!REPORT OF INDEPENDENT REGIS (4)!REPORT OF INDEPENDENT REGIS (5)!REPORT OF INDEPENDENT REGIS (6)!REPORT OF INDEPENDENT REGIS (8)!REPORT OF INDEPENDENT REGIS (9)!REPORT OF INDEPENDENT REGI (10)!REPORT OF INDEPENDENT REGI (11)!REPORT OF INDEPENDENT REGI (12)!REPORT OF INDEPENDENT REGI (13)!REPORT OF INDEPENDENT REGI (14)!REPORT OF INDEPENDENT REGI (15)!REPORT OF INDEPENDENT REGI (16)!REPORT OF INDEPENDENT REGI (17)!REPORT OF INDEPENDENT REGI (18)U } $ } } $ } y                         $PIONEER NATURAL RESOURCES CO 11-K 06/28/2010/'REPORT OF INDEPENDENT REGISTERED PUBLIC December 31, ~ f ~ b    1 )Net assets available for benefits per the~ .Ѹ1 ~ ") !accompanying financial statements.&Adjustment from fair value to contract~ 6 ~ 2*value for certain fully benefit-responsiveinvestment contracts2*Net assets available for benefits per Form~ bZ1~ "~ U$____________________________1)Created by Morningstar Document Research.0(http://documentresearch.morningstar.com/2sg[O+j=u-=PF0*8X> @       l  H dMbP?_*+%,&٭e2?'٭e2?(٭e2?)٭e2?",D/?? NO TITLE!REPORT OF INDEPENDENT REGISTERE!REPORT OF INDEPENDENT REGIS (1)!REPORT OF INDEPENDENT REGIS (2)!REPORT OF INDEPENDENT REGIS (3)!REPORT OF INDEPENDENT REGIS (4)!REPORT OF INDEPENDENT REGIS (5)!REPORT OF INDEPENDENT REGIS (6)!REPORT OF INDEPENDENT REGIS (7)!REPORT OF INDEPENDENT REGIS (9)!REPORT OF INDEPENDENT REGI (10)!REPORT OF INDEPENDENT REGI (11)!REPORT OF INDEPENDENT REGI (12)!REPORT OF INDEPENDENT REGI (13)!REPORT OF INDEPENDENT REGI (14)!REPORT OF INDEPENDENT REGI (15)!REPORT OF INDEPENDENT REGI (16)!REPORT OF INDEPENDENT REGI (17)!REPORT OF INDEPENDENT REGI (18)U } U5} $ }      $PIONEER NATURAL RESOURCES CO 11-K 06/28/2010/'REPORT OF INDEPENDENT REGISTERED PUBLIC0(Net increase in net assets available for~ */ 'benefits per the accompanying financial  statements4 ,Less: Adjustment from fair value to contract ~ 2 *value for certain fully benefit-responsiveinvestment contracts"Net increase per Form 5500~ r$____________________________1)Created by Morningstar Document Research.0(http://documentresearch.morningstar.com/.sg[Or<=PF0*8X> @* l  I˦8 dMbP?_*+%,&٭e2?'٭e2?(٭e2?)٭e2?",D/?? NO TITLE!REPORT OF INDEPENDENT REGISTERE!REPORT OF INDEPENDENT REGIS (1)!REPORT OF INDEPENDENT REGIS (2)!REPORT OF INDEPENDENT REGIS (3)!REPORT OF INDEPENDENT REGIS (4)!REPORT OF INDEPENDENT REGIS (5)!REPORT OF INDEPENDENT REGIS (6)!REPORT OF INDEPENDENT REGIS (7)!REPORT OF INDEPENDENT REGIS (8)!REPORT OF INDEPENDENT REGI (10)!REPORT OF INDEPENDENT REGI (11)!REPORT OF INDEPENDENT REGI (12)!REPORT OF INDEPENDENT REGI (13)!REPORT OF INDEPENDENT REGI (14)!REPORT OF INDEPENDENT REGI (15)!REPORT OF INDEPENDENT REGI (16)!REPORT OF INDEPENDENT REGI (17)!REPORT OF INDEPENDENT REGI (18)U } } $ }  '} $ } 1} $ }  I    $PIONEER NATURAL RESOURCES CO 11-K 06/28/2010/'REPORT OF INDEPENDENT REGISTERED PUBLIC (c)   (b) + #Description of investment including  (e)  % Identity of issuer, borrower, (  maturity date, rate of interest,  Current (a)  lessor, or similar party ) !collateral, par or maturity value  Value         *( Vanguard Fiduciary Trust Company/'Vanguard PRIMECAP Fund - 566,668 shares~ | *( Vanguard Fiduciary Trust Company0(Vanguard 500 Index Fund - 199,515 shares~ B *( Vanguard Fiduciary Trust Company1)Vanguard Windsor II Fund - 768,635 shares~ V *( Vanguard Fiduciary Trust Company*"Vanguard Prime Money Market Fund -17,576,791 shares~ ^0( Vanguard Fiduciary Trust Company/'American Funds Euro Pacific Growth Fund -~ .+278,063 shares *( Vanguard Fiduciary Trust Company-%Vanguard Retirement Savings Trust V -9,498,991 shares~ C *( Vanguard Fiduciary Trust Company( Vanguard Total Bond Market IndexFund - 784,041 shares~ J *( Vanguard Fiduciary Trust Company+#Vanguard Intermediate-Term TreasuryFund -~ J641,173 shares *( Vanguard Fiduciary Trust Company1)Vanguard Wellington Fund - 198,737 shares~ ]( Vanguard Fiduciary Trust Company-%Sentinel Small Company Fund - 837,815~ b(Bshares *( Vanguard Fiduciary Trust Company/'Vanguard Inflation-Protected SecuritiesDlsg[OoBDJ0kSGQ !"#$%&'()*+,-./0123456789:;<=>?     Fund - 414,571 shares  ~ Ǝ= !*!(! Vanguard Fiduciary Trust Company!.!&Vanguard Target Retirement 2015 fund -!!!"""""290,452 shares""~ "F #*#(# Vanguard Fiduciary Trust Company#.#&Vanguard Target Retirement 2005 Fund -###$$$$$274,492 shares$$~ $v %*%(% Vanguard Fiduciary Trust Company%.%&Vanguard Target Retirement 2025 Fund -%%%&&&&&214,069 shares&&~ &z '*'(' Vanguard Fiduciary Trust Company'.'&Vanguard Target Retirement 2010 fund -'''(((((116,443 shares((~ (֑ )*)() Vanguard Fiduciary Trust Company).)&Vanguard Target Retirement 2020 fund -)))*****107,029 shares**~ *c +*+(+ Vanguard Fiduciary Trust Company+.+&Vanguard Target Retirement 2035 Fund -+++,,,,,172,618 shares,,~ ,lz -*-(- Vanguard Fiduciary Trust Company-0-(Vanguard Total International Stock Index---.....Fund -..~ .VSv/////134,535 shares00(0 Vanguard Fiduciary Trust Company0-0%Oppenheimer Developing Markets Fund -0001111159,892 shares11~ 12g22(2 Vanguard Fiduciary Trust Company2,2$Templeton Global Bond Fund - 106,82422~ 2:R33333shares 4*4(4 Vanguard Fiduciary Trust Company4-4%Vanguard Extended Market Index Fund -4445555536,216 shares55~ 5N7H66(6 Vanguard Fiduciary Trust Company6/6'PIMCO Total Return Fund - 98,041 shares66~ 6z@ 7*7(7 Vanguard Fiduciary Trust Company7.7&Vanguard Target Retirement 2045 Fund -7778888893,866 shares88~ 8BD 9*9(9 Vanguard Fiduciary Trust Company9.9&Vanguard Target Retirement 2030 Fund -99~ 9b2C:::::57,015 shares;;(; Vanguard Fiduciary Trust Company;0;(Jennison Natural Resources Fund - 19,423;;~ ;5<<<<<shares==(= Vanguard Fiduciary Trust Company=/='Loomis Sayles Bond Fund - 64,990 shares==~ =f4 >*>(> Vanguard Fiduciary Trust Company>.>&Vanguard Target Retirement 2040 Fund ->>~ >&2?????43,017 sharesD%lr[D-oVC+8M@ABCDEFGH @*@(@ Vanguard Fiduciary Trust Company@.@&Vanguard Total Stock Market Index Fund@@@AAAA A-AA~ A @:HHGGFF    l   dMbP?_*+%,&٭e2?'٭e2?(٭e2?)٭e2?",D/?? NO TITLE!REPORT OF INDEPENDENT REGISTERE!REPORT OF INDEPENDENT REGIS (1)!REPORT OF INDEPENDENT REGIS (2)!REPORT OF INDEPENDENT REGIS (3)!REPORT OF INDEPENDENT REGIS (4)!REPORT OF INDEPENDENT REGIS (5)!REPORT OF INDEPENDENT REGIS (6)!REPORT OF INDEPENDENT REGIS (7)!REPORT OF INDEPENDENT REGIS (8)!REPORT OF INDEPENDENT REGIS (9)!REPORT OF INDEPENDENT REGI (11)!REPORT OF INDEPENDENT REGI (12)!REPORT OF INDEPENDENT REGI (13)!REPORT OF INDEPENDENT REGI (14)!REPORT OF INDEPENDENT REGI (15)!REPORT OF INDEPENDENT REGI (16)!REPORT OF INDEPENDENT REGI (17)!REPORT OF INDEPENDENT REGI (18)U } $} <(} 2} $ }      $PIONEER NATURAL RESOURCES CO 11-K 06/28/2010/'REPORT OF INDEPENDENT REGISTERED PUBLIC( Vanguard Fiduciary Trust Company*"Royce Premier Fund - 29,596 shares~ v (  Vanguard Fiduciary Trust Company, $AIM Real Estate Fund - 17,367 shares  ~ " (  Vanguard Fiduciary Trust Company/ 'JP Morgan Small Cap Equity Fund - 9,443  ~ ZM   shares (  Vanguard Fiduciary Trust Company2 *Artisan Mid Cap Value Fund - 12,951 shares  ~ 6( Vanguard Fiduciary Trust Company+#Columbia Acorn International Fund -~ R<  5,851 shares *( Vanguard Fiduciary Trust Company+#Vanguard Target Retirement Income -~ K 15,930 shares( Vanguard Fiduciary Trust Company1)T. Rowe Price Mid-Cap Growth Fund - 3,297~ " shares( Vanguard Fiduciary Trust Company.&Royce Total Return Fund - 1,883 shares~ =Fayez Sarofim & Co.,$Sarofim Equity Fund - 197,948 shares~ Z; *)!Pioneer Natural Resources Company.&Pioneer Natural Resources Stock Fund -~ 1,139,434 units *Participants loans0(Interest rates range from 4.25% to 9.25%~ :]~ N1$____________________________1)Created by Morningstar Document Research.0(http://documentresearch.morningstar.com/BI Xsg[O5zY)j R =PF0*8X> @" l  w dMbP?_*+%,&٭e2?'٭e2?(٭e2?)٭e2?",D/?? NO TITLE!REPORT OF INDEPENDENT REGISTERE!REPORT OF INDEPENDENT REGIS (1)!REPORT OF INDEPENDENT REGIS (2)!REPORT OF INDEPENDENT REGIS (3)!REPORT OF INDEPENDENT REGIS (4)!REPORT OF INDEPENDENT REGIS (5)!REPORT OF INDEPENDENT REGIS (6)!REPORT OF INDEPENDENT REGIS (7)!REPORT OF INDEPENDENT REGIS (8)!REPORT OF INDEPENDENT REGIS (9)!REPORT OF INDEPENDENT REGI (10)!REPORT OF INDEPENDENT REGI (12)!REPORT OF INDEPENDENT REGI (13)!REPORT OF INDEPENDENT REGI (14)!REPORT OF INDEPENDENT REGI (15)!REPORT OF INDEPENDENT REGI (16)!REPORT OF INDEPENDENT REGI (17)!REPORT OF INDEPENDENT REGI (18)U } } } 0     $PIONEER NATURAL RESOURCES CO 11-K 06/28/2010/'REPORT OF INDEPENDENT REGISTERED PUBLICDate: June 28, 2010 By:/s/ Larry N. Paulsen   Larry N. Paulsen  0 (Member of Pioneer Natural Resources USA,   Inc.  * "401(k) and Matching Plan Committee$____________________________1)Created by Morningstar Document Research.0(http://documentresearch.morningstar.com/(Tsg[OY=PF0*8X> @ l   dMbP?_*+%,&٭e2?'٭e2?(٭e2?)٭e2?",D/?? NO TITLE!REPORT OF INDEPENDENT REGISTERE!REPORT OF INDEPENDENT REGIS (1)!REPORT OF INDEPENDENT REGIS (2)!REPORT OF INDEPENDENT REGIS (3)!REPORT OF INDEPENDENT REGIS (4)!REPORT OF INDEPENDENT REGIS (5)!REPORT OF INDEPENDENT REGIS (6)!REPORT OF INDEPENDENT REGIS (7)!REPORT OF INDEPENDENT REGIS (8)!REPORT OF INDEPENDENT REGIS (9)!REPORT OF INDEPENDENT REGI (10)!REPORT OF INDEPENDENT REGI (11)!REPORT OF INDEPENDENT REGI (13)!REPORT OF INDEPENDENT REGI (14)!REPORT OF INDEPENDENT REGI (15)!REPORT OF INDEPENDENT REGI (16)!REPORT OF INDEPENDENT REGI (17)!REPORT OF INDEPENDENT REGI (18)U } } } 0     $PIONEER NATURAL RESOURCES CO 11-K 06/28/2010/'REPORT OF INDEPENDENT REGISTERED PUBLICDate: June 28, 2010 By:/s/ Richard P. Dealy   Richard P. Dealy  0 (Member of Pioneer Natural Resources USA,   Inc.  * "401(k) and Matching Plan Committee$____________________________1)Created by Morningstar Document Research.0(http://documentresearch.morningstar.com/(Tsg[OY=PF0*8X> @ l  = dMbP?_*+%,&٭e2?'٭e2?(٭e2?)٭e2?",D/?? NO TITLE!REPORT OF INDEPENDENT REGISTERE!REPORT OF INDEPENDENT REGIS (1)!REPORT OF INDEPENDENT REGIS (2)!REPORT OF INDEPENDENT REGIS (3)!REPORT OF INDEPENDENT REGIS (4)!REPORT OF INDEPENDENT REGIS (5)!REPORT OF INDEPENDENT REGIS (6)!REPORT OF INDEPENDENT REGIS (7)!REPORT OF INDEPENDENT REGIS (8)!REPORT OF INDEPENDENT REGIS (9)!REPORT OF INDEPENDENT REGI (10)!REPORT OF INDEPENDENT REGI (11)!REPORT OF INDEPENDENT REGI (12)!REPORT OF INDEPENDENT REGI (14)!REPORT OF INDEPENDENT REGI (15)!REPORT OF INDEPENDENT REGI (16)!REPORT OF INDEPENDENT REGI (17)!REPORT OF INDEPENDENT REGI (18)U } } } 0     $PIONEER NATURAL RESOURCES CO 11-K 06/28/2010/'REPORT OF INDEPENDENT REGISTERED PUBLICDate: June 28, 2010 By:/s/ Mark H. Kleinman   Mark H. Kleinman  0 (Member of Pioneer Natural Resources USA,   Inc.  * "401(k) and Matching Plan Committee$____________________________1)Created by Morningstar Document Research.0(http://documentresearch.morningstar.com/(Tsg[OY=PF0*8X> @ l   dMbP?_*+%,&٭e2?'٭e2?(٭e2?)٭e2?",D/?? NO TITLE!REPORT OF INDEPENDENT REGISTERE!REPORT OF INDEPENDENT REGIS (1)!REPORT OF INDEPENDENT REGIS (2)!REPORT OF INDEPENDENT REGIS (3)!REPORT OF INDEPENDENT REGIS (4)!REPORT OF INDEPENDENT REGIS (5)!REPORT OF INDEPENDENT REGIS (6)!REPORT OF INDEPENDENT REGIS (7)!REPORT OF INDEPENDENT REGIS (8)!REPORT OF INDEPENDENT REGIS (9)!REPORT OF INDEPENDENT REGI (10)!REPORT OF INDEPENDENT REGI (11)!REPORT OF INDEPENDENT REGI (12)!REPORT OF INDEPENDENT REGI (13)!REPORT OF INDEPENDENT REGI (15)!REPORT OF INDEPENDENT REGI (16)!REPORT OF INDEPENDENT REGI (17)!REPORT OF INDEPENDENT REGI (18)U } } } 0     $PIONEER NATURAL RESOURCES CO 11-K 06/28/2010/'REPORT OF INDEPENDENT REGISTERED PUBLICDate: June 28, 2010 By:/s/ Kerry D. Scott   Kerry D. Scott  0 (Member of Pioneer Natural Resources USA,   Inc.  * "401(k) and Matching Plan Committee$____________________________1)Created by Morningstar Document Research.0(http://documentresearch.morningstar.com/(Tsg[O] =PF0*8X> @ l   dMbP?_*+%,&٭e2?'٭e2?(٭e2?)٭e2?",D/?? NO TITLE!REPORT OF INDEPENDENT REGISTERE!REPORT OF INDEPENDENT REGIS (1)!REPORT OF INDEPENDENT REGIS (2)!REPORT OF INDEPENDENT REGIS (3)!REPORT OF INDEPENDENT REGIS (4)!REPORT OF INDEPENDENT REGIS (5)!REPORT OF INDEPENDENT REGIS (6)!REPORT OF INDEPENDENT REGIS (7)!REPORT OF INDEPENDENT REGIS (8)!REPORT OF INDEPENDENT REGIS (9)!REPORT OF INDEPENDENT REGI (10)!REPORT OF INDEPENDENT REGI (11)!REPORT OF INDEPENDENT REGI (12)!REPORT OF INDEPENDENT REGI (13)!REPORT OF INDEPENDENT REGI (14)!REPORT OF INDEPENDENT REGI (16)!REPORT OF INDEPENDENT REGI (17)!REPORT OF INDEPENDENT REGI (18)U } } } 0     $PIONEER NATURAL RESOURCES CO 11-K 06/28/2010/'REPORT OF INDEPENDENT REGISTERED PUBLICDate: June 28, 2010 By:/s/ Susan A. Spratlen   Susan A. Spratlen  0 (Member of Pioneer Natural Resources USA,   Inc.  * "401(k) and Matching Plan Committee$____________________________1)Created by Morningstar Document Research.0(http://documentresearch.morningstar.com/(Tsg[OW=PF0*8X> @ l  b dMbP?_*+%,&٭e2?'٭e2?(٭e2?)٭e2?",D/?? NO TITLE!REPORT OF INDEPENDENT REGISTERE!REPORT OF INDEPENDENT REGIS (1)!REPORT OF INDEPENDENT REGIS (2)!REPORT OF INDEPENDENT REGIS (3)!REPORT OF INDEPENDENT REGIS (4)!REPORT OF INDEPENDENT REGIS (5)!REPORT OF INDEPENDENT REGIS (6)!REPORT OF INDEPENDENT REGIS (7)!REPORT OF INDEPENDENT REGIS (8)!REPORT OF INDEPENDENT REGIS (9)!REPORT OF INDEPENDENT REGI (10)!REPORT OF INDEPENDENT REGI (11)!REPORT OF INDEPENDENT REGI (12)!REPORT OF INDEPENDENT REGI (13)!REPORT OF INDEPENDENT REGI (14)!REPORT OF INDEPENDENT REGI (15)!REPORT OF INDEPENDENT REGI (17)!REPORT OF INDEPENDENT REGI (18)U } } } 0     $PIONEER NATURAL RESOURCES CO 11-K 06/28/2010/'REPORT OF INDEPENDENT REGISTERED PUBLICDate: June 28, 2010 By:/s/ Douglas R. Hull   Douglas R. Hull  0 (Member of Pioneer Natural Resources USA,   Inc.  * "401(k) and Matching Plan Committee$____________________________1)Created by Morningstar Document Research.0(http://documentresearch.morningstar.com/(Tsg[O[ =PF0*8X> @ l   dMbP?_*+%,&٭e2?'٭e2?(٭e2?)٭e2?",D/?? NO TITLE!REPORT OF INDEPENDENT REGISTERE!REPORT OF INDEPENDENT REGIS (1)!REPORT OF INDEPENDENT REGIS (2)!REPORT OF INDEPENDENT REGIS (3)!REPORT OF INDEPENDENT REGIS (4)!REPORT OF INDEPENDENT REGIS (5)!REPORT OF INDEPENDENT REGIS (6)!REPORT OF INDEPENDENT REGIS (7)!REPORT OF INDEPENDENT REGIS (8)!REPORT OF INDEPENDENT REGIS (9)!REPORT OF INDEPENDENT REGI (10)!REPORT OF INDEPENDENT REGI (11)!REPORT OF INDEPENDENT REGI (12)!REPORT OF INDEPENDENT REGI (13)!REPORT OF INDEPENDENT REGI (14)!REPORT OF INDEPENDENT REGI (15)!REPORT OF INDEPENDENT REGI (16)!REPORT OF INDEPENDENT REGI (18)U } } } 0     $PIONEER NATURAL RESOURCES CO 11-K 06/28/2010/'REPORT OF INDEPENDENT REGISTERED PUBLICDate: June 28, 2010 By:/s/ Paul McDonald   Paul McDonald  0 (Member of Pioneer Natural Resources USA,   Inc.  * "401(k) and Matching Plan Committee$____________________________1)Created by Morningstar Document Research.0(http://documentresearch.morningstar.com/(Tsg[O_=PF0*8X> @ l   dMbP?_*+%,&٭e2?'٭e2?(٭e2?)٭e2?",D/?? NO TITLE!REPORT OF INDEPENDENT REGISTERE!REPORT OF INDEPENDENT REGIS (1)!REPORT OF INDEPENDENT REGIS (2)!REPORT OF INDEPENDENT REGIS (3)!REPORT OF INDEPENDENT REGIS (4)!REPORT OF INDEPENDENT REGIS (5)!REPORT OF INDEPENDENT REGIS (6)!REPORT OF INDEPENDENT REGIS (7)!REPORT OF INDEPENDENT REGIS (8)!REPORT OF INDEPENDENT REGIS (9)!REPORT OF INDEPENDENT REGI (10)!REPORT OF INDEPENDENT REGI (11)!REPORT OF INDEPENDENT REGI (12)!REPORT OF INDEPENDENT REGI (13)!REPORT OF INDEPENDENT REGI (14)!REPORT OF INDEPENDENT REGI (15)!REPORT OF INDEPENDENT REGI (16)!REPORT OF INDEPENDENT REGI (17)U } } } 0     $PIONEER NATURAL RESOURCES CO 11-K 06/28/2010/'REPORT OF INDEPENDENT REGISTERED PUBLICDate: June 28, 2010 By:/s/ Andrew Quarles   Andrew Quarles  0 (Member of Pioneer Natural Resources USA,   Inc.  * "401(k) and Matching Plan Committee$____________________________1)Created by Morningstar Document Research.0(http://documentresearch.morningstar.com/(Tsg[O] =PF0*8X> @ Root Entry FBook    !"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefghijklmnopqrstuvwxyz{|}~