Initial Statement of Beneficial Ownership (3)

FORM 3	UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES	OMB APPROVAL OMB Number: 3235-0104 Estimated average burden hours per response... 0.5
	Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940

1. Name and Address of Reporting Person ^*

Hiller Michael

2. Date of Event Requiring Statement (MM/DD/YYYY) 1/1/2021

3. Issuer Name and Ticker or Trading Symbol

Builders FirstSource, Inc. [BLDR]

(Last) (First) (Middle)

C/O BUILDERS FIRSTSOURCE, INC., 2001 BRYAN ST., SUITE 1600

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

_____ Director _____ 10% Owner
___X___ Officer (give title below) _____ Other (specify below)
President - Central Division /

(Street)

DALLAS, TX 75201

(City) (State) (Zip)

5. If Amendment, Date Original Filed(MM/DD/YYYY)

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

_X_ Form filed by One Reporting Person
___ Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Beneficially Owned
1.Title of Security (Instr. 4)	2. Amount of Securities Beneficially Owned (Instr. 4)	3. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	4. Nature of Indirect Beneficial Ownership (Instr. 5)

*Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)*
1. Title of Derivate Security (Instr. 4)	2. Date Exercisable and Expiration Date (MM/DD/YYYY)		3. Title and Amount of Securities Underlying Derivative Security (Instr. 4)		4. Conversion or Exercise Price of Derivative Security	5. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 5)	6. Nature of Indirect Beneficial Ownership (Instr. 5)
1. Title of Derivate Security (Instr. 4)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares	4. Conversion or Exercise Price of Derivative Security		6. Nature of Indirect Beneficial Ownership (Instr. 5)

Explanation of Responses:

Remarks:
On January 1, 2021, the merger (the "Merger") of Boston Merger Sub I Inc., a subsidiary of the Issuer, with and into BMC Stock Holdings, Inc., pursuant to the Agreement and Plan of Merger, dated as of August 26, 2020, was completed. This report reflects the beneficial ownership of the Reporting Person at the time of completion of the Merger and does not include the securities of the Issuer acquired by the Reporting Person upon the completion of the Merger. The Reporting Person will file a Form 4 reflecting the Reporting Person's acquisition of securities of the Issuer in connection with the completion of the Merger.

No securities are beneficially owned.

Reporting Owners
Reporting Owner Name / Address	Relationships
Reporting Owner Name / Address	Director	10% Owner	Officer	Other
Hiller Michael C/O BUILDERS FIRSTSOURCE, INC. 2001 BRYAN ST., SUITE 1600 DALLAS, TX 75201			President - Central Division