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	OMB APPROVAL OMB Number: 3235-0287 Estimated average burden hours per response: 0.5
	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* First Reserve GP XI, Inc. (Last) (First) (Middle) ONE LAFAYETTE PLACE (Street) GREENWICH CT 06830 (City) (State) (Zip)	2. Issuer Name and Ticker or Trading Symbol Cobalt International Energy, Inc. [ CIE ]	5. Relationship of Reporting Person(s) to Issuer (Check all applicable) Director X 10% Owner Officer (give title below) Other (specify below)
	3. Date of Earliest Transaction (Month/Day/Year) 05/10/2013
	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)
			Code	V	Amount	(A) or (D)	Price
Common Stock	05/10/2013		S		11,866,539	D	$26.62	27,396,278	I	See footnotes(1)(2)(4)
Common Stock	05/10/2013		S		3,965,765	D	$26.62	9,155,763	I	See footnotes(1)(3)(4)

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)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares

1. Name and Address of Reporting Person* First Reserve GP XI, Inc. (Last) (First) (Middle) ONE LAFAYETTE PLACE (Street) GREENWICH CT 06830 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* First Reserve GP XI, L.P. (Last) (First) (Middle) ONE LAFAYETTE PLACE (Street) GREENWICH CT 06830 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* FIRST RESERVE FUND XI L P (Last) (First) (Middle) ONE LAFAYETTE PLACE (Street) GREENWICH CT 06830 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* FR XI Onshore AIV, L.P. (Last) (First) (Middle) ONE LAFAYETTE PLACE (Street) GREENWICH CT 06830 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* MACAULAY WILLIAM E (Last) (First) (Middle) ONE LAFAYETTE PLACE (Street) GREENWICH CT 06830 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

Explanation of Responses:

1. This Form 4 is filed on behalf of William E. Macaulay, First Reserve GP XI, Inc. ("GP XI Inc."), First Reserve GP XI, L.P. ("GP XI"), First Reserve Fund XI, L.P. ("Fund XI") and FR XI Onshore AIV, L.P. ("Onshore AIV"). GP XI is the general partner of Fund XI and Onshore AIV, and GP XI Inc. is the general partner of GP XI. Mr. Macaulay is a director of GP XI Inc. and has the right to appoint a majority of the board of directors of GP XI Inc. In such capacities, each of Mr. Macaulay, GP XI and GP XI Inc. may be deemed to have an indirect beneficial ownership in the shares of common stock held by Fund XI and Onshore AIV.

2. These shares of Common Stock are held by Fund XI.

3. These shares of Common Stock are held by Onshore AIV.

4. Pursuant to Rule 16a-1(a)(4) under the Securities Exchange Act of 1934, as amended, each of the Reporting Persons herein states that this filing shall not be deemed an admission that such Reporting Person is the beneficial owner of any of the shares of Common Stock covered by this Statement. Additionally, each Reporting Person, other than Fund XI and Onshore AIV with respect to the securities held directly by each of them, disclaims beneficial ownership of such securities except to the extent of its pecuniary interest therein.

Remarks:

First Reserve GP XI, Inc., by Anne E. Gold, Chief Administrative Officer, Secretary and Assistant Treasure is signing for itself as the designated filer, as well as in the capacity of general partner of First Reserve GP XI, L.P and as attorney-in-fact for William E. Macaulay. First Reserve GP XI, L.P. is signing for itself and in its capacity as general partner of First Reserve Fund XI, L.P. and FR XI Onshore AIV, L.P.

	First Reserve GP XI, Inc., By: /s/ Anne E. Gold, Name: Anne E. Gold, Title: Chief Compliance Officer/Secretary	05/10/2013
	First Reserve GP XI, L.P., By: First Reserve GP XI, Inc., its general partner, By: /s/ Anne E. Gold, Name: Anne E. Gold, Title: Chief Compliance Officer/Secretary	05/10/2013
	First Reserve Fund XI, L.P., By: First Reserve GP XI, L.P., its general partner, By: First Reserve GP XI, Inc., its general partner, By: /s/ Anne E. Gold, Name: Anne E. Gold, Title: Chief Compliance Officer/Secretary	05/10/2013
	FR XI Onshore AIV, L.P., By: First Reserve GP XI, L.P., its general partner, By: First Reserve GP XI, Inc., its general partner, By: /s/ Anne E. Gold, Name: Anne E. Gold, Title: Chief Compliance Officer/Secretary	05/10/2013
	WILLIAM E. MACAULAY, By: /s/ Anne E. Gold, Name: Anne E. Gold, Attorney-in-Fact	05/10/2013
	** Signature of Reporting Person	Date
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* 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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