PSE / Prime Skyline Limited - Pengajuan SECLaporan Tahunan, Pernyataan Proksi

- FORM 15-12B

FORM 15-12B UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 15 CERTIFICATION AND NOTICE OF TERMINATION OF REGISTRATION UNDER SECTION 12(g) OF THE SECURITIES EXCHANGE ACT OF 1934 OR SUSPENSION OF DUTY TO FILE REPORTS UNDER SECTIONS 13 AND 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Commission File Number 001-34032 Pioneer Southwest Energy Partners L.P. (Exact name of r

EX-99.25

NOTIFICATION OF THE REMOVAL FROM LISTING AND REGISTRATION OF THE STATED SECURITIES The New York Stock Exchange hereby notifies the SEC of its intention to remove the entire class of the stated securities from listing and registration on the Exchange at the opening of business on December 31, 2013, pursuant to the provisions of Rule 12d2-2 (a).

PSE / Pioneer Southwest Energy Partners L.p. / Pioneer Natural Resources Co - SCHEDULE 13D AMENDMENT NO. 4 Activist Investment

Schedule 13D Amendment No. 4 SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13D/A Under the Securities Exchange Act of 1934 (Amendment No. 4) Pioneer Southwest Energy Partners L.P. (Name of Issuer) Common Units (Title of Class of Securities) 72388B 106 (CUSIP Number) Mark S. Berg Pioneer Southwest Energy Partners L.P. 5205 N. O’Connor Blvd., Suite 200 Irving, Texas 75039 Tel: (

- S-8 POS

S-8 POS As filed with the Securities and Exchange Commission on December 17, 2013 Registration No.

Pioneer Natural Resources Company Completes Merger of Pioneer Southwest Energy Partners L.P.

EX-99.1 Exhibit 99.1 News Release Pioneer Natural Resources Company Completes Merger of Pioneer Southwest Energy Partners L.P. Dallas, Texas, December 17, 2013 – Pioneer Natural Resources Company (NYSE: PXD) (“Pioneer”) and Pioneer Southwest Energy Partners L.P. (NYSE: PSE) (“Pioneer Southwest”) today jointly announced the completion of the merger of Pioneer Southwest with a wholly-owned subsidiar

- POS AM

POS AM As filed with the Securities and Exchange Commission on December 17, 2013 Registration No.

- POS AM

POS AM As filed with the Securities and Exchange Commission on December 17, 2013 Registration No.

Regulation FD Disclosure, Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers, Termination of a Material Definitive Agreement, Material Modification to Rights of Security Holders, Notice of Delisting or Failure to Satisfy a Continued Listing Rule or Standard; Transfer of Listing, Financial Statements and Exhibits, Submission of Matters to a Vote of Security Holders - FORM 8-K

Form 8-K UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): December 17, 2013 PIONEER SOUTHWEST ENERGY PARTNERS L.P. (Exact name of registrant as specified in its charter) Delaware 001-34032 26-0388421 (State or other jurisdiction of

Other Events - 8-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): December 9, 2013 PIONEER SOUTHWEST ENERGY PARTNERS L.P. (Exact name of registrant as specified in its charter) Delaware 001-34032 26-0388421 (State or other jurisdiction of incorporat

- DEFM14A

DEFM14A Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.

Quarterly Report - FORM 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q ý QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended September 30, 2013 or ¨ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File Number: 001-34032 PIONEER SOUTHWES

Merger Prospectus - PSE NOVEMBER 4, 2013 EARNINGS RELEASE 8-K

SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): November 4, 2013 PIONEER SOUTHWEST ENERGY PARTNERS L.P. (Exact name of registrant as specified in its charter) Delaware 001-34032 26-0388421 (State or other jurisdiction of incorporation) (Commissi

Financial Statements and Exhibits, Results of Operations and Financial Condition - PSE NOVEMBER 4, 2013 EARNINGS RELEASE 8-K

SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): November 4, 2013 PIONEER SOUTHWEST ENERGY PARTNERS L.P. (Exact name of registrant as specified in its charter) Delaware 001-34032 26-0388421 (State or other jurisdiction of incorporation) (Commissi

Pioneer Southwest Energy Partners L.P. Reports Third Quarter 2013 Financial and Operating Results

EXHIBIT 99.1 News Release Pioneer Southwest Energy Partners L.P. Reports Third Quarter 2013 Financial and Operating Results Dallas, Texas, November 4, 2013 - Pioneer Southwest Energy Partners L.P. (“Pioneer Southwest” or “the Partnership”) (NYSE: PSE) today announced financial and operating results for the quarter ended September 30, 2013. Pioneer Southwest reported third quarter net income of $16

Pioneer Southwest Energy Partners L.P. Reports Third Quarter 2013 Financial and Operating Results

EXHIBIT 99.1 News Release Pioneer Southwest Energy Partners L.P. Reports Third Quarter 2013 Financial and Operating Results Dallas, Texas, November 4, 2013 - Pioneer Southwest Energy Partners L.P. (“Pioneer Southwest” or “the Partnership”) (NYSE: PSE) today announced financial and operating results for the quarter ended September 30, 2013. Pioneer Southwest reported third quarter net income of $16

Entry into a Material Definitive Agreement, Financial Statements and Exhibits - FORM 8-K

Form 8-K SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): October 25, 2013 PIONEER SOUTHWEST ENERGY PARTNERS L.P. (Exact name of registrant as specified in its charter) Delaware 001-34032 26-0388421 (State or other jurisdiction of incorporation)

AMENDMENT NO. 1 TO AGREEMENT AND PLAN OF MERGER

EX-2.1 Exhibit 2.1 EXECUTION VERSION AMENDMENT NO. 1 TO AGREEMENT AND PLAN OF MERGER This Amendment No. 1 (the “Amendment”) to the Agreement and Plan of Merger, dated as of August 9, 2013 (the “Agreement”), by and among Pioneer Natural Resources Company, a Delaware corporation (“PNR”), Pioneer Natural Resources USA, Inc., a Delaware corporation and wholly-owned subsidiary of PNR (“PNR USA”), PNR A

Merger Prospectus - FORM 8-K

Form 8-K SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): October 25, 2013 PIONEER SOUTHWEST ENERGY PARTNERS L.P. (Exact name of registrant as specified in its charter) Delaware 001-34032 26-0388421 (State or other jurisdiction of incorporation)

AMENDMENT NO. 1 TO AGREEMENT AND PLAN OF MERGER

EX-2.1 Exhibit 2.1 EXECUTION VERSION AMENDMENT NO. 1 TO AGREEMENT AND PLAN OF MERGER This Amendment No. 1 (the “Amendment”) to the Agreement and Plan of Merger, dated as of August 9, 2013 (the “Agreement”), by and among Pioneer Natural Resources Company, a Delaware corporation (“PNR”), Pioneer Natural Resources USA, Inc., a Delaware corporation and wholly-owned subsidiary of PNR (“PNR USA”), PNR A

Regulation FD Disclosure, Results of Operations and Financial Condition - PSE OCTOBER 18, 2013 DERIVATIVE 8-K

SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): October 18, 2013 PIONEER SOUTHWEST ENERGY PARTNERS L.P. (Exact name of registrant as specified in its charter) Delaware 001-34032 26-0388421 (State or other jurisdiction of incorporation) (Commissi

AGREEMENT AND PLAN OF MERGER by and among PIONEER NATURAL RESOURCES COMPANY PIONEER NATURAL RESOURCES USA, INC. PNR ACQUISITION COMPANY, LLC PIONEER NATURAL RESOURCES GP LLC PIONEER SOUTHWEST ENERGY PARTNERS L.P. Dated as of August 9, 2013 TABLE OF C

EX-2.1 Exhibit 2.1 EXECUTION VERSION AGREEMENT AND PLAN OF MERGER by and among PIONEER NATURAL RESOURCES COMPANY PIONEER NATURAL RESOURCES USA, INC. PNR ACQUISITION COMPANY, LLC and PIONEER NATURAL RESOURCES GP LLC PIONEER SOUTHWEST ENERGY PARTNERS L.P. Dated as of August 9, 2013 TABLE OF CONTENTS ARTICLE I CERTAIN DEFINITIONS 2 Section 1.1 Certain Definitions 2 Section 1.2 Interpretation 9 ARTICL

VOTING AGREEMENT BY AND AMONG PIONEER NATURAL RESOURCES COMPANY PIONEER NATURAL RESOURCES USA, INC. PNR ACQUISITION COMPANY, LLC PIONEER NATURAL RESOURCES GP LLC PIONEER SOUTHWEST ENERGY PARTNERS L.P. Dated as of August 9, 2013 VOTING AGREEMENT

EX-10.1 Exhibit 10.1 EXECUTION VERSION VOTING AGREEMENT BY AND AMONG PIONEER NATURAL RESOURCES COMPANY PIONEER NATURAL RESOURCES USA, INC. PNR ACQUISITION COMPANY, LLC AND PIONEER NATURAL RESOURCES GP LLC PIONEER SOUTHWEST ENERGY PARTNERS L.P. Dated as of August 9, 2013 VOTING AGREEMENT This VOTING AGREEMENT, dated as of August 9, 2013 (this “Agreement”), is entered into by and among Pioneer Natur

VOTING AGREEMENT BY AND AMONG PIONEER NATURAL RESOURCES COMPANY PIONEER NATURAL RESOURCES USA, INC. PNR ACQUISITION COMPANY, LLC PIONEER NATURAL RESOURCES GP LLC PIONEER SOUTHWEST ENERGY PARTNERS L.P. Dated as of August 9, 2013 VOTING AGREEMENT

EX-10.1 Exhibit 10.1 EXECUTION VERSION VOTING AGREEMENT BY AND AMONG PIONEER NATURAL RESOURCES COMPANY PIONEER NATURAL RESOURCES USA, INC. PNR ACQUISITION COMPANY, LLC AND PIONEER NATURAL RESOURCES GP LLC PIONEER SOUTHWEST ENERGY PARTNERS L.P. Dated as of August 9, 2013 VOTING AGREEMENT This VOTING AGREEMENT, dated as of August 9, 2013 (this “Agreement”), is entered into by and among Pioneer Natur

Regulation FD Disclosure, Entry into a Material Definitive Agreement, Financial Statements and Exhibits - FORM 8-K

Form 8-K UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): August 9, 2013 PIONEER SOUTHWEST ENERGY PARTNERS L.P. (Exact name of registrant as specified in its charter) Delaware 001-34032 26-0388421 (State or other jurisdiction of inc

Merger Prospectus - FORM 8-K

Form 8-K UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): August 9, 2013 PIONEER SOUTHWEST ENERGY PARTNERS L.P. (Exact name of registrant as specified in its charter) Delaware 001-34032 26-0388421 (State or other jurisdiction of inc

PSE / Pioneer Southwest Energy Partners L.p. / Pioneer Natural Resources Co - SCHEDULE 13D AMENDMENT NO. 3 Activist Investment

Schedule 13D Amendment No. 3 SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13D/A Under the Securities Exchange Act of 1934 (Amendment No. 3) Pioneer Southwest Energy Partners L.P. (Name of Issuer) Common Units (Title of Class of Securities) 72388B 106 (CUSIP Number) Mark S. Berg Pioneer Southwest Energy Partners L.P. 5205 N. O’Connor Blvd., Suite 200 Irving, Texas 75039 Tel: (

Pioneer Natural Resources Company and Pioneer Southwest Energy Partners L.P. Announce Merger Agreement

EX-99.1(A) 4 d579755dex991a.htm EX-99.1(A) Exhibit 99.1 News Release Pioneer Natural Resources Company and Pioneer Southwest Energy Partners L.P. Announce Merger Agreement Dallas, Texas, August 12, 2013 – Pioneer Natural Resources Company (NYSE: PXD) (“Pioneer”) and Pioneer Southwest Energy Partners L.P. (NYSE: PSE) (“Pioneer Southwest”) today announced the execution of a definitive agreement and

Pioneer Natural Resources Company and Pioneer Southwest Energy Partners L.P. Announce Merger Agreement

EX-99.1(a) Exhibit 99.1 News Release Pioneer Natural Resources Company and Pioneer Southwest Energy Partners L.P. Announce Merger Agreement Dallas, Texas, August 12, 2013 – Pioneer Natural Resources Company (NYSE: PXD) (“Pioneer”) and Pioneer Southwest Energy Partners L.P. (NYSE: PSE) (“Pioneer Southwest”) today announced the execution of a definitive agreement and plan of merger (the “Merger Agre

AGREEMENT AND PLAN OF MERGER by and among PIONEER NATURAL RESOURCES COMPANY PIONEER NATURAL RESOURCES USA, INC. PNR ACQUISITION COMPANY, LLC PIONEER NATURAL RESOURCES GP LLC PIONEER SOUTHWEST ENERGY PARTNERS L.P. Dated as of August 9, 2013 TABLE OF C

EX-2.1 Exhibit 2.1 EXECUTION VERSION AGREEMENT AND PLAN OF MERGER by and among PIONEER NATURAL RESOURCES COMPANY PIONEER NATURAL RESOURCES USA, INC. PNR ACQUISITION COMPANY, LLC and PIONEER NATURAL RESOURCES GP LLC PIONEER SOUTHWEST ENERGY PARTNERS L.P. Dated as of August 9, 2013 TABLE OF CONTENTS ARTICLE I CERTAIN DEFINITIONS 2 Section 1.1 Certain Definitions 2 Section 1.2 Interpretation 9 ARTICL

Merger Prospectus - PSE JULY 31, 2013 EARNINGS RELEASE 8-K

SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): July 31, 2013 PIONEER SOUTHWEST ENERGY PARTNERS L.P. (Exact name of registrant as specified in its charter) Delaware 001-34032 26-0388421 (State or other jurisdiction of incorporation) (Commission

Financial Statements and Exhibits, Results of Operations and Financial Condition - PSE JULY 31, 2013 EARNINGS RELEASE 8-K

SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): July 31, 2013 PIONEER SOUTHWEST ENERGY PARTNERS L.P. (Exact name of registrant as specified in its charter) Delaware 001-34032 26-0388421 (State or other jurisdiction of incorporation) (Commission

Pioneer Southwest Energy Partners L.P. Reports Second Quarter 2013 Financial and Operating Results

EXHIBIT 99.1 News Release Pioneer Southwest Energy Partners L.P. Reports Second Quarter 2013 Financial and Operating Results Dallas, Texas, July 31, 2013 - Pioneer Southwest Energy Partners L.P. (“Pioneer Southwest” or “the Partnership”) (NYSE: PSE) today announced financial and operating results for the quarter ended June 30, 2013. Pioneer Southwest reported second quarter net income of $30 milli

Pioneer Southwest Energy Partners L.P. Reports Second Quarter 2013 Financial and Operating Results

EXHIBIT 99.1 News Release Pioneer Southwest Energy Partners L.P. Reports Second Quarter 2013 Financial and Operating Results Dallas, Texas, July 31, 2013 - Pioneer Southwest Energy Partners L.P. (“Pioneer Southwest” or “the Partnership”) (NYSE: PSE) today announced financial and operating results for the quarter ended June 30, 2013. Pioneer Southwest reported second quarter net income of $30 milli

Regulation FD Disclosure, Results of Operations and Financial Condition

SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): July 18, 2013 PIONEER SOUTHWEST ENERGY PARTNERS L.P. (Exact name of registrant as specified in its charter) Delaware 001-34032 26-0388421 (State or other jurisdiction of incorporation) (Commission

Pioneer Southwest Energy Partners L.P. Receives Buyout Proposal from Pioneer Natural Resources Company

EX-99.1 Exhibit 99.1 News Release Pioneer Southwest Energy Partners L.P. Receives Buyout Proposal from Pioneer Natural Resources Company Dallas, Texas, May 7, 2013 – Pioneer Southwest Energy Partners L.P. (NYSE:PSE) (“Pioneer Southwest”) today announced that the chairman of the Conflicts Committee of the board of directors of Pioneer Southwest’s general partner received a proposal from Pioneer Nat

Pioneer Southwest Energy Partners L.P. Receives Buyout Proposal from Pioneer Natural Resources Company

EX-99.1 Exhibit 99.1 News Release Pioneer Southwest Energy Partners L.P. Receives Buyout Proposal from Pioneer Natural Resources Company Dallas, Texas, May 7, 2013 – Pioneer Southwest Energy Partners L.P. (NYSE:PSE) (“Pioneer Southwest”) today announced that the chairman of the Conflicts Committee of the board of directors of Pioneer Southwest’s general partner received a proposal from Pioneer Nat

PSE / Pioneer Southwest Energy Partners L.p. / Pioneer Natural Resources Co - SCHEDULE 13D AMENDMENT NO. 2 Activist Investment

Schedule 13D Amendment No. 2 SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13D/A Under the Securities Exchange Act of 1934 (Amendment No. 2) Pioneer Southwest Energy Partners L.P. (Name of Issuer) Common Units (Title of Class of Securities) 72388B 106 (CUSIP Number) Mark S. Berg Pioneer Southwest Energy Partners L.P. 5205 N. O’Connor Blvd., Suite 200 Irving, Texas 75039 Tel: (

2

EX-99.1 Exhibit 99.1 May 7, 2013 Mr. Arthur L. Smith Chairman, Conflicts Committee Pioneer Natural Resources GP LLC 5205 N. O’Connor Blvd., Suite 200 Irving, Texas 75039-3746 Dear Mr. Smith: Pioneer Natural Resources Company (“PNR”) is pleased to submit a proposal (the “Proposal”) pursuant to which PNR would acquire all of the outstanding common units of Pioneer Southwest Energy Partners L.P. (the

Merger Prospectus - FORM 8-K

Form 8-K UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): May 7, 2013 PIONEER SOUTHWEST ENERGY PARTNERS L.P. (Exact name of registrant as specified in its charter) Delaware 001-34032 26-0388421 (State or other jurisdiction of incorp

Financial Statements and Exhibits, Other Events - FORM 8-K

Form 8-K UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): May 7, 2013 PIONEER SOUTHWEST ENERGY PARTNERS L.P. (Exact name of registrant as specified in its charter) Delaware 001-34032 26-0388421 (State or other jurisdiction of incorp

Financial Statements and Exhibits, Results of Operations and Financial Condition - PSE MAY 1, 2013 EARNINGS RELEASE 8-K

SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): May 1, 2013 PIONEER SOUTHWEST ENERGY PARTNERS L.P. (Exact name of registrant as specified in its charter) Delaware 001-34032 26-0388421 (State or other jurisdiction of incorporation) (Commission Fi

Pioneer Southwest Energy Partners L.P. Reports First Quarter 2013 Financial and Operating Results

EXHIBIT 99.1 News Release Pioneer Southwest Energy Partners L.P. Reports First Quarter 2013 Financial and Operating Results Dallas, Texas, May 1, 2013 - Pioneer Southwest Energy Partners L.P. (“Pioneer Southwest” or “the Partnership”) (NYSE: PSE) today announced financial and operating results for the quarter ended March 31, 2013. Pioneer Southwest reported first quarter net income of $17 million,

Regulation FD Disclosure, Results of Operations and Financial Condition - PSE APRIL 22, 2013 DERIVATIVE 8-K

SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): April 22, 2013 PIONEER SOUTHWEST ENERGY PARTNERS L.P. (Exact name of registrant as specified in its charter) Delaware 001-34032 26-0388421 (State or other jurisdiction of incorporation) (Commission

PIONEER SOUTHWEST ENERGY PARTNERS L.P. INDEMNIFICATION AGREEMENT

EXHIBIT 10.1 PIONEER SOUTHWEST ENERGY PARTNERS L.P. INDEMNIFICATION AGREEMENT This Agreement (“Agreement”) is made and entered into as of the 7th day of March, 2013, by and between Pioneer Southwest Energy Partners L.P., a Delaware limited partnership (the “Partnership”), and Phillip A. Gobe (“Indemnitee”). RECITALS A. Highly competent and experienced persons are reluctant to serve companies as di

Entry into a Material Definitive Agreement, Financial Statements and Exhibits - 8-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): March 7, 2013 PIONEER SOUTHWEST ENERGY PARTNERS L.P. (Exact name of registrant as specified in its charter) Delaware 001-34032 26-0388421 (State or other jurisdiction of incorporation

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February 28, 2013 Via EDGAR Submission and Overnight Mail Securities and Exchange Commission Division of Corporation Finance 100 F Street, N.

Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers - 8-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): February 20, 2013 PIONEER SOUTHWEST ENERGY PARTNERS L.P. (Exact name of registrant as specified in its charter) Delaware 001-34032 26-0388421 (State or other jurisdiction of incorpora

Pioneer Southwest Energy Partners L.P. Reports Fourth Quarter 2012 Financial and Operating Results

EXHIBIT 99.1 News Release Pioneer Southwest Energy Partners L.P. Reports Fourth Quarter 2012 Financial and Operating Results Dallas, Texas, February 13, 2013 - Pioneer Southwest Energy Partners L.P. (“Pioneer Southwest” or “the Partnership”) (NYSE: PSE) today announced financial and operating results for the quarter ended December 31, 2012. Pioneer Southwest reported fourth quarter net income of $

Financial Statements and Exhibits, Results of Operations and Financial Condition - PSE FEB 13, 2013 EARNINGS RELEASE 8-K

SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): February 13, 2013 PIONEER SOUTHWEST ENERGY PARTNERS L.P. (Exact name of registrant as specified in its charter) Delaware 001-34032 26-0388421 (State or other jurisdiction of incorporation) (Commiss

Regulation FD Disclosure, Results of Operations and Financial Condition

SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): January 29, 2013 PIONEER SOUTHWEST ENERGY PARTNERS L.P. (Exact name of registrant as specified in its charter) Delaware 001-34032 26-0388421 (State or other jurisdiction of incorporation) (Commissi

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January 15, 2013 Via EDGAR Submission and Overnight Mail Securities and Exchange Commission Division of Corporation Finance 100 F Street, N.

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January 7, 2013 Via EDGAR Submission and Overnight Mail United States Securities and Exchange Commission Division of Corporation Finance 100 F Street, N.

Regulation FD Disclosure - 8-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): December 3, 2012 PIONEER SOUTHWEST ENERGY PARTNERS L.P. (Exact name of registrant as specified in its charter) Delaware 001-34032 26-0388421 (State or other jurisdiction of incorporat

Financial Statements and Exhibits, Results of Operations and Financial Condition

SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): October 31, 2012 PIONEER SOUTHWEST ENERGY PARTNERS L.P. (Exact name of registrant as specified in its charter) Delaware 001-34032 26-0388421 (State or other jurisdiction of incorporation) (Commissi

Pioneer Southwest Energy Partners L.P. Reports Third Quarter 2012 Financial and Operating Results

EXHIBIT 99.1 News Release Pioneer Southwest Energy Partners L.P. Reports Third Quarter 2012 Financial and Operating Results Dallas, Texas, October 31, 2012 - Pioneer Southwest Energy Partners L.P. (“Pioneer Southwest” or “the Partnership”) (NYSE:PSE) today announced financial and operating results for the quarter ended September 30, 2012. Pioneer Southwest reported third quarter net income of $6 m

Regulation FD Disclosure, Results of Operations and Financial Condition - PSE OCTOBER 18, 2012 DERIVATIVE 8-K

SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): October 18, 2012 PIONEER SOUTHWEST ENERGY PARTNERS L.P. (Exact name of registrant as specified in its charter) Delaware 001-34032 26-0388421 (State or other jurisdiction of incorporation) (Commissi

Regulation FD Disclosure - PSE OCT 1, 2012 DERIVATIVE 8-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): October 1, 2012 PIONEER SOUTHWEST ENERGY PARTNERS L.P. (Exact name of registrant as specified in its charter) Delaware 001-34032 26-0388421 (State or other jurisdiction of incorporati

PIONEER SOUTHWEST ENERGY PARTNERS L.P. RATIO OF EARNINGS TO FIXED CHARGES (in thousands, except ratios) Pioneer Southwest Energy Partners L.P. (a) Year Ended December 31, Six Months Ended June 30, Six Months Ended June 30, 2007 2008 2009 2010 2011 20

Computation of ratio of earnings to fixed charges Exhibit 12.1 PIONEER SOUTHWEST ENERGY PARTNERS L.P. RATIO OF EARNINGS TO FIXED CHARGES (in thousands, except ratios) Pioneer Southwest Energy Partners L.P. (a) Year Ended December 31, Six Months Ended June 30, Six Months Ended June 30, 2007 2008 2009 2010 2011 2011 2012 Income from continuing operations before income taxes $ 87,436 $ 121,102 $ 26,3

- FORM S-3

FORM S-3 Table of Contents As filed with the Securities and Exchange Commission on August 17, 2012 Registration No.

Pioneer Southwest Energy Partners L.P. Reports Second Quarter 2012 Financial and Operating Results

EXHIBIT 99.1 News Release Pioneer Southwest Energy Partners L.P. Reports Second Quarter 2012 Financial and Operating Results Dallas, Texas, July 31, 2012 - Pioneer Southwest Energy Partners L.P. (“Pioneer Southwest” or “the Partnership”) (NYSE:PSE) today announced financial and operating results for the quarter ended June 30, 2012. Pioneer Southwest reported second quarter net income of $65 millio

Financial Statements and Exhibits, Results of Operations and Financial Condition

SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): July 31, 2012 PIONEER SOUTHWEST ENERGY PARTNERS L.P. (Exact name of registrant as specified in its charter) Delaware 001-34032 26-0388421 (State or other jurisdiction of incorporation) (Commission

Pioneer Southwest Energy Partners L.P. Provides Production and Financial Update for the Second Quarter of 2012

EXHIBIT 99.1 News Release Pioneer Southwest Energy Partners L.P. Provides Production and Financial Update for the Second Quarter of 2012 Dallas, Texas, July 18, 2012 - Pioneer Southwest Energy Partners L.P. (NYSE:PSE) (“Pioneer Southwest” or “the Partnership”) today provided updates on the Partnership’s expected production and commodity price realizations for the second quarter of 2012. Second Qua

Financial Statements and Exhibits, Results of Operations and Financial Condition

SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): July 18, 2012 PIONEER SOUTHWEST ENERGY PARTNERS L.P. (Exact name of registrant as specified in its charter) Delaware 001-34032 26-0388421 (State or other jurisdiction of incorporation) (Commission

Financial Statements and Exhibits, Results of Operations and Financial Condition - PSE MAY 2, 2012 EARNINGS RELEASE 8-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): May 2, 2012 PIONEER SOUTHWEST ENERGY PARTNERS L.P. (Exact name of registrant as specified in its charter) Delaware 001-34032 26-0388421 (State or other jurisdiction of incorporation)

Pioneer Southwest Energy Partners L.P. Reports First Quarter 2012 Financial and Operating Results

EXHIBIT 99.1 News Release Pioneer Southwest Energy Partners L.P. Reports First Quarter 2012 Financial and Operating Results Dallas, Texas, May 2, 2012 - Pioneer Southwest Energy Partners L.P. (“Pioneer Southwest” or “the Partnership”) (NYSE:PSE) today announced financial and operating results for the quarter ended March 31, 2012. Pioneer Southwest reported first quarter net income of $14 million,

Regulation FD Disclosure, Results of Operations and Financial Condition

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): April 25, 2012 PIONEER SOUTHWEST ENERGY PARTNERS L.P. (Exact name of registrant as specified in its charter) Delaware 001-34032 26-0388421 (State or other jurisdiction of incorporatio

AMENDED AND RESTATED CREDIT AGREEMENT Dated as of March 29, 2012 PIONEER SOUTHWEST ENERGY PARTNERS L.P., as the Borrower, BANK OF AMERICA, N.A., as Administrative Agent, Swing Line Lender L/C Issuer, WELLS FARGO BANK, N. A., as Syndication Agent, BAN

EXHIBIT 10.1 Execution Version Published CUSIP Number: AMENDED AND RESTATED CREDIT AGREEMENT Dated as of March 29, 2012 among PIONEER SOUTHWEST ENERGY PARTNERS L.P., as the Borrower, BANK OF AMERICA, N.A., as Administrative Agent, Swing Line Lender and L/C Issuer, WELLS FARGO BANK, N. A., as Syndication Agent, BANK OF MONTREAL, and CITIBANK, N.A. as Co-Documentation Agents and The Other Lenders Pa

Entry into a Material Definitive Agreement, Financial Statements and Exhibits, Creation of a Direct Financial Obligation or an Obligation under an Off-Balance Sheet Arrangement of a Registrant

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): March 29, 2012 PIONEER SOUTHWEST ENERGY PARTNERS L.P. (Exact name of registrant as specified in its charter) Delaware 001-34032 26-0388421 (State or other jurisdiction of incorporatio

Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers - PSE FEB 28, 2012 8-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): February 22, 2012 PIONEER SOUTHWEST ENERGY PARTNERS L.P. (Exact name of registrant as specified in its charter) Delaware 001-34032 26-0388421 (State or other jurisdiction of incorpora

Pioneer Southwest Energy Partners L.P. Reports Fourth Quarter 2011 Financial and Operating Results

EXHIBIT 99.1 News Release Pioneer Southwest Energy Partners L.P. Reports Fourth Quarter 2011 Financial and Operating Results Dallas, Texas, February 6, 2012 - Pioneer Southwest Energy Partners L.P. (“Pioneer Southwest” or “the Partnership”) (NYSE:PSE) today announced financial and operating results for the quarter ended December 31, 2011. Pioneer Southwest reported a fourth quarter net loss of $7

Financial Statements and Exhibits, Results of Operations and Financial Condition - PSE FEB 6, 2012 EARNINGS RELEASE 8-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): February 6, 2012 PIONEER SOUTHWEST ENERGY PARTNERS L.P. (Exact name of registrant as specified in its charter) Delaware 001-34032 26-0388421 (State or other jurisdiction of incorporat

Regulation FD Disclosure, Results of Operations and Financial Condition - PSE JAN 18, 2012 DERIVATIVE 8-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): January 18, 2012 PIONEER SOUTHWEST ENERGY PARTNERS L.P. (Exact name of registrant as specified in its charter) Delaware 001-34032 26-0388421 (State or other jurisdiction of incorporat

Regulation FD Disclosure - PSE JAN 9, 2012 8-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): January 9, 2012 PIONEER SOUTHWEST ENERGY PARTNERS L.P. (Exact name of registrant as specified in its charter) Delaware 001-34032 26-0388421 (State or other jurisdiction of incorporati

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Correspondence Letter December 8, 2011 VIA EDGAR AND FACSIMILE Securities and Exchange Commission Division of Corporation Finance 100 F Street, N.

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Correspondence Letter December 8, 2011 U.S. Securities and Exchange Commission Division of Corporation Finance 101 F Street, N.E. Washington, D.C. 20549 Attn: Ms. Anne Nguyen Parker Branch Chief Re: Pioneer Southwest Energy Partners L.P. Registration Statement on Form S-3 Filed November 21, 2011 File No. 333-178074 Form 10-K for Fiscal Year Ended December 31, 2010 Filed February 25, 2011 File No.

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Correspondence Letter December 5, 2011 U.S. Securities and Exchange Commission Division of Corporation Finance 101 F Street, N.E. Washington, D.C. 20549 Attn: Ms. Anne Nguyen Parker Branch Chief Re: Pioneer Southwest Energy Partners L.P. Registration Statement on Form S-3 Filed November 21, 2011 File No. 333-178074 Form 10-K for Fiscal Year Ended December 31, 2010 Filed February 25, 2011 File No.