–ѕа°±б>ю€ ю€€€ю€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€ l …бЅњјв\pThe Free Software Foundation BдЬ=PF0*8X@Н"ЈЏ1іР Helvetica1іРCourier1іР Courier New1іЉ Courier New1іР 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)ах€ ј ах€ фј ах€ фј ах€ фј ах€ фј ах€ фј ах€ фј ах€ фј ах€ фј ах€ фј ах€ фј ах€ фј ах€ фј ах€ фј ах€ фј а ј а+х€ шј а)х€ шј а,х€ шј а*х€ шј а х€ шј а –И ~~ња ЎИ ~~ња#ЎИ ~~ња"ЎИ ~~ња ЎИ ~~ња8#№И ~~њУА€УА€УА€УА€УА€УА€Тв8€€€€€€€€€€€€АААААААААјјјАААЩЩ€Щ3f€€ћћ€€ff€ААfћћћ€А€€€€€€ААААА€ћ€ћ€€ћ€ћ€€ЩЩћ€€ЩћћЩ€€ћЩ3f€3ћћЩћ€ћ€Щ€fffЩЦЦЦ3f3Щf333Щ3Щ3f33Щ«««Е*ACCOUNTING FIRMЕACCOUNTING FIRM (1)Е”ACCOUNTING FIRM (2)Е&ACCOUNTING FIRM (3) l … .µЭ dь©с“MbP?_*+ВА%€БјМ,БЅГД&¬ў≠e2ў?'¬ў≠e2ў?(¬ў≠e2ў?)¬ў≠e2ў?°",D/а?а?дACCOUNTING FIRM (1)ACCOUNTING FIRM (2)ACCOUNTING FIRM (3)U } ґ7} <} ™ .ббббббббб б б б бббббббббббббббббббб$PIONEER NATURAL RESOURCES CO 11-K 06/28/2006ACCOUNTING FIRM     December 31,    2005 2004"Investments at fair value:  Vanguard PRIMECAP Fund~ Ќ ~ &`" Vanguard Windsor II Fund~ Ъс(~ ґћM! Vanguard 500 Index Fund~ b z~ "Е**" Vanguard Prime Money Market Fund~ Оl~ ЛZ+# Vanguard Retirement Savings Trust~ zј~ Њ†!,$ Vanguard International Growth Fund~ Тл©~ Кvд  Vanguard Explorer Fund~ 2х®~ к≤3+ Vanguard Short-Term Investment-Grade Fund~ V2S~ N°w/' Vanguard Total Bond Market Index Fund~ VM%~ Гб( Vanguard Asset Allocation Fund~ ∆U ~ Кж„6. Vanguard Inflation-Protected Securities Fund~ ќЋ~ Ґf§ Sarofim Equity Fund~ К≤≈~ ЊЗю Pioneer Stock Fund~ .o~ €X„DlЎ€»€≤€Ъ€s€[€C€+€€ыю„юњюУюЗю{юoюcю=юээїэzэ0эеьЩьYььЈыoыы№ъ б!б"б#б$б%б&б'б(б)б*б+б,б-б ~ NZ\"~ Ґ€9%!Participants loans receivable~ !fµҐ~ !*єУ"""#~ #≤€"~ # ЄЌ $Contributions receivable~ $~ $цШ3%+Unallocated accrued administrative expenses~ %юQ€€~ %“:€€&&&+'# Net assets available for benefits~ 'Ѓaю"~ 'ОМЌ((()*$+____________________________1,)Created by Morningstar Document Research.0-(http://documentresearch.morningstar.com/„ †Ў€У€o€G€€іюРюEю!юю юбэ=PF0*8X> ґ@е--,,++ l … )7` dь©с“MbP?_*+ВА%€БјМ,БЅГД&¬ў≠e2ў?'¬ў≠e2ў?(¬ў≠e2ў?)¬ў≠e2ў?°",D/а?а?дACCOUNTING FIRMACCOUNTING FIRM (2)ACCOUNTING FIRM (3)U } џ>} y )ббббббббб б б б бббббббббббббббббббб$PIONEER NATURAL RESOURCES CO 11-K 06/28/2006ACCOUNTING FIRM   7 /Additions to net assets available for benefits:& Interest and dividend income~ ^-  Employer contributions~ ^¬% Participants' contributions~ rƒµ7/ Net appreciation in fair value of investments~ :`t Rollovers~ Zњ! Other income~ ¬~ zрs:2Deductions from net assets available for benefits:' Distributions to participants~ “ч>! Administrative expenses~ К#~ ZC91Net increase in net assets available for benefits~ "’0<4Net assets available for benefits, beginning of year~ ОМЌ„D™lЎ€»€≤€¶€Л€€s€g€[€O€C€7€ьюƒюТю[ююнэ≈э≠эУэ{э=ээ—ьєьЯьЗь{ь0ь б!б"б#б$б%б&б'б(б  !6".Net assets available for benefits, end of year~ "Ѓaю"##$%$&____________________________1')Created by Morningstar Document Research.0((http://documentresearch.morningstar.com/„б†и€№€Ф€|€p€d€<€=PF0*8X> ґ@е((''&& l … К% dь©с“MbP?_*+ВА%€БјМ,БЅГД&¬ў≠e2ў?'¬ў≠e2ў?(¬ў≠e2ў?)¬ў≠e2ў?°",D/а?а?дACCOUNTING FIRMACCOUNTING FIRM (1)ACCOUNTING FIRM (3)U } 6 Net appreciation in fair value of investments~ :`t$____________________________1)Created by Morningstar Document Research.0(http://documentresearch.morningstar.com/„0H§Ў€»€≤€¶€Л€€s€g€[€O€C€€ юЩюБю1ююююўэ=PF0*8X> ґ@е l … ;Ѓ1Э: dь©с“MbP?_*+ВА%€БјМ,БЅГД&¬ў≠e2ў?'¬ў≠e2ў?(¬ў≠e2ў?)¬ў≠e2ў?°",D/а?а?дACCOUNTING FIRMACCOUNTING FIRM (1)ACCOUNTING FIRM (2)U } } Ж6} Т0} ™ ;ббббббббб б б б бббббббббббббббббббб$PIONEER NATURAL RESOURCES CO 11-K 06/28/2006ACCOUNTING FIRM   (c)   Description of  (b) investment including  Identity of issuer, maturity date, rate of (e)borrower, lessor,!interest, collateral, parCurrent (a)or similar partyor maturity valueValue  *( Vanguard Fiduciary Trust Company Vanguard PRIMECAP Fund -522,000 shares~ Ќ   *( Vanguard Fiduciary Trust Company"Vanguard Windsor II Fund -690,787 shares~ Ъс(  *( Vanguard Fiduciary Trust Company!Vanguard 500 Index Fund -163,390 shares~ b z  *( Vanguard Fiduciary Trust Company*"Vanguard Prime Money Market Fund -10,167,173 shares~ Оl  *( Vanguard Fiduciary Trust Company+#Vanguard Retirement Savings Trust -7,341,854 shares~ zј  *( Vanguard Fiduciary Trust Company,$Vanguard International Growth Fund -332,299 shares~ Тл©  *( Vanguard Fiduciary Trust Company Vanguard Explorer Fund -92,697 shares~ 2х®„D lЎ€»€≤€О€[€7€€пюЋю§юrю7юџэzэ!ээ ээьЮь^ьэыљы]ыыіъqъъ≈щZщщ б!б"б#б$б%б&б'б(б)б*б+б,б-б.б/б0б1б2б3б4б5б6б7б8б9б:б  *(  Vanguard Fiduciary Trust Company, $Vanguard Short-Term Investment-Grade!!!Fund - 528,772 shares~ !V2S " *(" Vanguard Fiduciary Trust Company/"'Vanguard Total Bond Market Index Fund -###477,680 shares~ #VM% $ *($ Vanguard Fiduciary Trust Company($ Vanguard Asset Allocation Fund -%%%171,625 shares~ %∆U  & *(& Vanguard Fiduciary Trust Company/&'Vanguard Inflation-Protected Securities'''Fund - 273,588 shares~ 'ќЋ ( *(Fayez Sarofim & Co.(Sarofim Equity Fund -)))218,196 shares~ )К≤≈ * *)*!Pioneer Natural Resources Company**"Pioneer Stock Fund - 462,386 units~ *.o + *%+Participants loans receivable/+'Interest rates range from 5.0% to 10.5%~ +fµҐ,,,,-...~ .≤€"////0112 *Party-in-i2*Party-in-interest34 Note: Colum54-Column (d) is not applicable since all invest#4investments are participant5 direc5 directed.67$8____________________________19)Created by Morningstar Document Research.0:(http://documentresearch.morningstar.com/„:ІХ€N€аю†ю9ющэЛэDэхьµь=ьƒыФыИыVы&ыыыЌъЅъJъъъъёщ=PF0*8X> ґ@е::9988 Root Entry€€€€€€€€ јFю€€€Book €€€€€€€€€€€€ 4; ю€€€ю€€€э€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€