Statement of Changes in Beneficial Ownership (Form 4)

FORM 4 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 that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

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 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person * MANSFIELD KEITH 2. Issuer Name and Ticker or Trading Symbol Business First Bancshares, Inc. [BFST] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director _____ 10% Owner __X__ Officer (give title below) _____ Other (specify below) EVP&COO of b1Bank (Last) (First) (Middle) 500 LAUREL STREET, SUITE 101 3. Date of Earliest Transaction (Month/Day/Year) 03/01/2026 (Street) BATON ROUGE, LA 70801 4. If Amendment, Date Original Filed (Month/Day/Year) 6. Individual or Joint/Group Filing (Check Applicable Line) _X_ Form filed by One Reporting Person ___ 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 03/01/2026 M 1,926 A (3) 83,339(1)(2) D COMMON STOCK 03/01/2026 F 676 D $27.3 82,663(1)(2) D

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

Restricted Stock Units

(3)

03/01/2026

M

1,926

(3)

(3)

Common Stock

1,926

(3)

7,634

D

Restricted Stock Units

$ 0

03/02/2026

A

5,740(4)

(4)

(4)

Common Stock

5,740

(4)

13,374(5)

D

Reporting Owners

Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
MANSFIELD KEITH 500 LAUREL STREET, SUITE 101 BATON ROUGE, LA 70801			EVP&COO of b1Bank

Signatures

/s/ Heather Roemer, as attorney-in-fact for Keith Mansfield		03/03/2026
**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)	Includes 3,776 shares of unvested restricted stock granted on February 1, 2024, which will vest on March 31, 2026. Under the terms of the relevant restricted stock grants, the reported shares of unvested restricted stock are subject to forfeiture upon the occurrence of certain events.
(2)	Includes 27,000 shares held by the reporting person's investment retirement account.
(3)	The reporting person received an award of 5,838 time-based restricted stock units on March 1, 2025, vesting in three substantially equal installments on the first, second, and third anniversary of the issuance date.
(4)	Reflects the grant of 5,740 time-based restricted stock units granted to the reporting person on March 2, 2026, of which 1,913 shares will vest on March 2, 2027, 1,913 shares will vest on March 2, 2028, and the remaining 1,914 shares will vest on March 2, 2029. Each time-based restricted stock unit is economically equivalent to one share of common stock of the issuer.
(5)	Includes: (a) 3,722 time-based restricted stock units granted to the reporting person on December 12, 2024, which will vest in two substantially equal installments on the second and third anniversary of the issuance date; (b) 3,912 time-based restricted stock units granted to the reporting person on March 1, 2025, which will vest in two substantially equal installments on the second and third anniversary of the issuance date; and (c) 5,740 time-based restricted stock units granted to the reporting person on March 2, 2026, which will vest in three substantially equal installments on the first, second, and third anniversary of the issuance date.

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