Sec Form 4 Filing - Warburg Pincus Private Equity X O&G, L.P. @ Laredo Petroleum Holdings, Inc. - 2013-08-19

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

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, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person Warburg Pincus Private Equity X O&G, L.P. 2. Issuer Name and Ticker or Trading Symbol Laredo Petroleum Holdings, Inc. [ LPI] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) X __ Director X __ 10% Owner _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) C/O WARBURG PINCUS & CO., 450 LEXINGTON AVENUE 3. Date of Earliest Transaction (MM/DD/YY) 08/19/2013 (Street) NEW YORK, NY10017 4. If Amendment, Date Original Filed (MM/DD/YY) 6. Individual or Joint/Group Filing (Check Applicable Line) _____ Form filed by One Reporting Person __ X __ Form filed by More than One Reporting Person (City) (State) (Zip)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned 1.Title of Security (Instr. 3) 2. Transaction Date (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 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) Code V Amount (A) or (D) Price Common Stock, par value $0.01 per share (''Common Stock'') 08/19/2013 S 585,487 D $ 22.9781 16,430,888 D ( 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 (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 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 (MM/DD/YY) 7. Title and Amount of Underlying Securities (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 of Derivative Security: Direct (D) or Indirect (I) (Instr. 4) 11. Nature of Indirect Beneficial Ownership (Instr. 4) Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other Warburg Pincus Private Equity X O&G, L.P. C/O WARBURG PINCUS & CO. 450 LEXINGTON AVENUE NEW YORK, NY10017 X X Warburg Pincus X Partners, L.P. C/O WARBURG PINCUS & CO. 450 LEXINGTON AVENUE NEW YORK, NY10017 X X Warburg Pincus X, L.P. C/O WARBURG PINCUS & CO. 450 LEXINGTON AVENUE NEW YORK, NY10017 X X Warburg Pincus X LLC C/O WARBURG PINCUS & CO. 450 LEXINGTON AVENUE NEW YORK, NY10017 X X Warburg Pincus Partners LLC C/O WARBURG PINCUS & CO. 450 LEXINGTON AVENUE NEW YORK, NY10017 X X WARBURG PINCUS & CO. C/O WARBURG PINCUS & CO. 450 LEXINGTON AVENUE NEW YORK, NY10017 X X WARBURG PINCUS LLC C/O WARBURG PINCUS & CO. 450 LEXINGTON AVENUE NEW YORK, NY10017 X KAYE CHARLES R C/O WARBURG PINCUS & CO. 450 LEXINGTON AVENUE NEW YORK, NY10017 X Landy Joseph P. C/O WARBURG PINCUS & CO. 450 LEXINGTON AVENUE NEW YORK, NY10017 X Signatures /s/ Scott A. Arenare, Attorney-in-Fact of Warburg Pincus & Co., as Managing Member of Warburg Pincus Partners LLC, as Sole Member of Warburg Pincus X LLC, as GP of Warburg Pincus X, L.P., as GP of Warburg Pincus Private Equity X O&G, L.P. 08/19/2013 Signature of Reporting Person Date

Explanation of Responses:

( 1 )See Exhibit 99.1; Note 1. ( 2 )See Exhibit 99.1; Note 2.

Remarks: Exhibit 99.1 - Explanation of Responses Exhibit 99.2 - Joint Filer Information Exhibit 99.3 - Joint Filers' Signatures *** The Power of Attorney given by Warburg Pincus & Co. was previously filed with the U.S. Securities & Exchange Commission on January 15, 2013 as an exhibit to a statement on Schedule 13D/A filed by Warburg Pincus Private Equity X, L.P. with respect to Talon Therapeutics, Inc. and is hereby incorporated by reference.

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).

Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
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