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 OF SECURITIES 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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(Print or Type Responses)

1. Name and Address of Reporting Person * Warburg Pincus Private Equity IX, L.P.   2. Issuer Name and Ticker or Trading Symbol Builders FirstSource, Inc. [BLDR] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director __X__ 10% Owner _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) C/O WARBURG PINCUS LLC, 450 LEXINGTON AVENUE 3. Date of Earliest Transaction (Month/Day/Year) 07/31/2015 (Street) NEW YORK, NY 10017 4. If Amendment, Date 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 (City) (State) (Zip) 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, par value $0.01 per share 07/31/2015   S   4,600,000 D $ 12.224 20,263,266 D (1) (2) (3)

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
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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 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 IX, L.P. C/O WARBURG PINCUS LLC 450 LEXINGTON AVENUE NEW YORK, NY 10017		X
Warburg Pincus IX GP L.P. C/O WARBURG PINCUS LLC 450 LEXINGTON AVE. NEW YORK, NY 10017		X
WPP GP LLC C/O WARBURG PINCUS LLC 450 LEXINGTON AVE. NEW YORK, NY 10017		X
Warburg Pincus Partners, L.P. C/O WARBURG PINCUS LLC 450 LEXINGTON AVE. NEW YORK, NY 10017		X
Warburg Pincus Partners GP LLC C/O WARBURG PINCUS LLC 450 LEXINGTON AVE. NEW YORK, NY 10017		X
WARBURG PINCUS & CO. 450 LEXINGTON AVE. NEW YORK, NY 10017		X
WARBURG PINCUS LLC 450 LEXINGTON AVE. NEW YORK, NY 10017		X
KAYE CHARLES R C/O WARBURG PINCUS LLC 450 LEXINGTON AVE. NEW YORK, NY 10017		X
Landy Joseph P. C/O WARBURG PINCUS LLC 450 LEXINGTON AVE. NEW YORK, NY 10017		X

Signatures

WARBURG PINCUS PRIVATE EQUITY IX, L.P., By: Warburg Pincus IX GP LP, its GP, By: WPP GP LLC, its GP, By: Warburg Pincus Partners L.P., its MM, By: Warburg Pincus Partners GP LLC, its GP, By: Warburg Pincus & Co., its MM, By: /s/ Robert B. Knauss, Partner		08/03/2015
**Signature of Reporting Person		Date
WARBURG PINCUS IX GP L.P., By: WPP GP LLC, its GP, By: Warburg Pincus Partners, L.P., its Managing Member, By: Warburg Pincus Partners GP LLC, its GP, By: Warburg Pincus & Co., its Managing Member, By: /s/ Robert B. Knauss, Partner		08/03/2015
**Signature of Reporting Person		Date
WPP GP LLC, By: Warburg Pincus Partners, L.P., its Managing Member, By: Warburg Pincus Partners GP LLC, its General Partner, By: Warburg Pincus & Co., its Managing Member, By: /s/ Robert B. Knauss, Partner		08/03/2015
**Signature of Reporting Person		Date
WARBURG PINCUS PARTNERS, L.P., By: Warburg Pincus Partners GP LLC, its General Partner, By: Warburg Pincus & Co., its Managing Member, By: /s/ Robert B. Knauss, Partner		08/03/2015
**Signature of Reporting Person		Date
WARBURG PINCUS PARTNERS GP LLC, By: Warburg Pincus & Co., its Managing Member, By: /s/ Robert B. Knauss, Partner		08/03/2015
**Signature of Reporting Person		Date
WARBURG PINCUS & CO., By: /s/ Robert B. Knauss, Partner		08/03/2015
**Signature of Reporting Person		Date
WARBURG PINCUS LLC, By: /s/ Robert B. Knauss, Managing Director		08/03/2015
**Signature of Reporting Person		Date
CHARLES R. KAYE, By: /s/ Robert B. Knauss, Attorney-in-Fact*		08/03/2015
**Signature of Reporting Person		Date
JOSEPH P. LANDY, By: /s/ Robert B. Knauss, Attorney-in-Fact*		08/03/2015
**Signature of Reporting Person		Date

Explanation of Responses:

*	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).
(1)	This Form 4 is filed on behalf of (i) Warburg Pincus Private Equity IX, L.P., a Delaware limited partnership ("WP IX"); (ii) Warburg Pincus IX GP L.P., a Delaware limited partnership ("WP IX GP"), the general partner of WP IX; (iii) WPP GP LLC, a Delaware limited liability company ("WPP GP"), the general partner of WP IX GP; (iv) Warburg Pincus Partners, L.P., a Delaware limited partnership ("WP Partners"), the sole member of WPP GP; (v) Warburg Pincus Partners GP LLC, a Delaware limited liability company ("WP Partners GP"), the general partner of WP Partners; (vi) Warburg Pincus & Co., a New York general partnership ("WP"), the managing member of WP Partners GP; (vii) Warburg Pincus LLC, a New York limited liability company ("WP LLC"), which manages WP IX; and (viii) Charles R. Kaye and Joseph P. Landy, who are Managing General Partners of WP and Managing Members and Co-Chief Executive Officers of WP LLC and may be deemed to control the entities listed in clauses (i) through (vii).
(2)	All shares of common stock, par value $0.01 per share (the "Common Stock"), of the Company that are reported herein are held by WP IX. By reason of the provisions of Rule 16a-1 of the Securities Exchange Act of 1934, as amended (the "Exchange Act"), WP IX GP, WPP GP, WP Partners, WP Partners GP, WP, WP LLC, Mr. Kaye and Mr. Landy may be deemed to be the beneficial owners of any securities that may be beneficially owned by WP IX. Each of WP IX GP, WPP GP, WP Partners, WP Partners GP, WP, WP LLC, Mr. Kaye and Mr. Landy disclaim beneficial ownership of all shares of Common Stock that may be deemed to be beneficially owned by WP IX, except to the extent of any indirect pecuniary interest therein.
(3)	(Continued from Footnote 2) This Form 4 shall not be deemed an admission that any reporting person, other than WP IX, or any other person referred to herein is a beneficial owner or any shares of Common Stock for purposes of Section 16 of the Exchange Act or for any other purpose or that any reporting person, other than WP IX, or other person has an obligation to file this Form 4.
Remarks: * The Power of Attorney given by each of Mr. Kaye and Mr. Landy was previously filed with the U.S. Securities & Exchange Commission on November 26, 2013 as an exhibit to a statement on Form 4 filed by Warburg Pincus Private Equity IX, L.P. with respect to Laredo Petroleum, Inc. (f/k/a Laredo Petroleum Holdings, Inc.) and is hereby incorporated by reference.

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