Builders FirstSource (BLDR) director awarded 2,558 RSUs, now holds 47,504 shares

Rhea-AI Filing Summary

Builders FirstSource, Inc. director Mark A. Alexander reported a grant of 2,558 shares of common stock in the form of restricted stock units under the company’s 2014 Incentive Plan. These units were awarded at no cash cost to him and increase his direct holdings to 47,504 shares.

The restricted stock units vest on May 14, 2027 and will convert into one share of common stock for each unit that vests. This is a routine, compensation-related equity award rather than an open-market stock purchase or sale.

Insider Trade Summary

1 transaction reported

Mixed 1 txn

Insider ALEXANDER MARK A

Role null

Type	Security	Shares	Price	Value
Grant/Award	Common Stock, par value $0.01 per share	2,558	$0.00	--

Holdings After Transaction: Common Stock, par value $0.01 per share — 47,504 shares (Direct, null)

Footnotes (1)

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Key Figures

RSU grant size: 2,558 restricted stock units Holdings after grant: 47,504 shares Grant price per share: $0.0000 per share

3 metrics

RSU grant size 2,558 restricted stock units Equity award to director on May 14, 2026

Holdings after grant 47,504 shares Total direct common stock holdings after transaction

Grant price per share $0.0000 per share Reported acquisition price for the awarded units

Key Terms

restricted stock units, 2014 Incentive Plan, vest

3 terms

restricted stock units financial

"Reflects the acquisition of restricted stock units pursuant to the Corporation's 2014 Incentive Plan."

Restricted stock units are a type of company reward where employees are promised shares of stock, but they only fully own these shares after meeting certain conditions, like staying with the company for a set time. They matter because they can become valuable assets and are often used to motivate employees to help the company succeed.

2014 Incentive Plan financial

"Reflects the acquisition of restricted stock units pursuant to the Corporation's 2014 Incentive Plan."

vest financial

"The restricted stock units vest on May 14, 2027 and entitle the reporting person to one share of common stock for each restricted stock unit that vests."

A vest is the process by which an employee earns the right to receive certain benefits or ownership interests, such as stock or retirement funds, over time. It’s similar to earning a reward gradually, ensuring that the benefit becomes fully yours only after a set period or meeting specific conditions. This makes it important for investors because it determines when they can actually claim or use those benefits.

Form 4 Insider Transactions: What Each Field Means →

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).

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

ALEXANDER MARK A

(Last) (First) (Middle)

C/O BUILDERS FIRSTSOURCE, INC.

6031 CONNECTION DR., STE. 400

(Street)

IRVING TEXAS 75039

(City) (State) (Zip)

UNITED STATES

(Country)

2. Issuer Name and Ticker or Trading Symbol
Builders FirstSource, Inc. [ BLDR ]

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

X	Director		10% Owner
	Officer (give title below)		Other (specify below)

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
05/14/2026

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

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

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

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	05/14/2026		A		2,558(1)	A	$0	47,504	D

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

Explanation of Responses:

1. Reflects the acquisition of restricted stock units pursuant to the Corporation's 2014 Incentive Plan. The restricted stock units vest on May 14, 2027 and entitle the reporting person to one share of common stock for each restricted stock unit that vests.

	/s/ Minator Azemi, by power of attorney	05/18/2026
	** 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).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.
* Form 4: SEC 1474 (03-26)