SEC FORM 4

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

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Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

1. Name and Address of Reporting Person^*

PIONEER NATURAL RESOURCES CO

(Last)

(First)

(Middle)

5205 N. O'CONNOR BLVD, SUITE 200

(Street)

IRVING

75039

(City)

(State)

(Zip)

2. Issuer Name and Ticker or Trading Symbol
Pioneer Southwest Energy Partners L.P. [ PSE ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

Director	X	10% Owner
Officer (give title below)	X	Other (specify below)
		Indirect Owner of Gen Partner

3. Date of Earliest Transaction (Month/Day/Year)
05/06/2008

4. If Amendment, Date of Original Filed (Month/Day/Year)

6. Individual or Joint/Group Filing (Check Applicable Line)

	Form filed by One Reporting Person
X	Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	Code	V	Amount	(A) or (D)	Price		6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
Common Units	05/06/2008		P		20,521,200	A	$19	20,521,200	I	See Footnote⁽¹⁾⁽²⁾

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares	8. Price of Derivative Security (Instr. 5)		10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)

1. Name and Address of Reporting Person^*

PIONEER NATURAL RESOURCES CO

(Last)

(First)

(Middle)

5205 N. O'CONNOR BLVD, SUITE 200

(Street)

IRVING

75039

(City)

(State)

(Zip)

Relationship of Reporting Person(s) to Issuer

Director	X	10% Owner
Officer (give title below)	X	Other (specify below)
		Indirect Owner of Gen Partner

1. Name and Address of Reporting Person^*

PIONEER NATURAL RESOURCES USA INC

(Last)

(First)

(Middle)

5205 N. O'CONNOR BLVD., SUITE 200

(Street)

IRVING

75039

(City)

(State)

(Zip)

Relationship of Reporting Person(s) to Issuer

Director		10% Owner
Officer (give title below)	X	Other (specify below)
		Direct Owner of Gen Partner

Explanation of Responses:

1. The securities reported on this Form 4 are held directly by Pioneer Natural Resources USA, Inc. ("Pioneer USA"). Pioneer USA is a wholly-owned subsidiary of Pioneer Natural Resources Company ("Pioneer"). Pioneer is an indirect beneficial owner of the reported securities. Pioneer USA is also a direct owner of the general partner of the Issuer.

2. On May 6, 2008, in connection with the Issuer's initial public offering, Pioneer USA contributed a portion of its ownership interest in the operating company to the Issuer in exchange for the reported securities, all in accordance with the Contribution Agreement, dated May 6, 2008, by and among Pioneer USA, the general partner and the Issuer.

Remarks:

	By: Mark H. Kleinman, Vice President	05/07/2008
	Mark H. Kleinman, Vice President	05/06/2008
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
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