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 * Zanco Joseph B 2. Issuer Name and Ticker or Trading Symbol Catalyst Bancorp, Inc. [CLST] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) __X__ Director _____ 10% Owner __X__ Officer (give title below) _____ Other (specify below) PRESIDENT AND CEO (Last) (First) (Middle) C/O CATALYST BANCORP INC, 235 N COURT ST 3. Date of Earliest Transaction (Month/Day/Year) 06/10/2026 (Street) OPELOUSAS, LA 70570 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 06/10/2026 A(1) 5,290 A $ 0 38,160(2)(3) D Common Stock 15,000 I By Spouse Common Stock 2,886.38(4) I By 401(k) Plan Common Stock 8,506.7075(5) I By ESOP Common Stock 22,009 I By IRA

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

Stock Option (Right to Buy)

$13.3

(6)

09/01/2032

Common Stock

52,900

52,900

D

Stock Option (Right to Buy)

$12.08

(7)

06/10/2035

Common Stock

13,225

13,225

D

Stock Option (Right to Buy)

$15.96

06/10/2026

A

13,225

06/10/2027(8)

06/10/2036

Common Stock

13,225

$ 0

13,225

D

Reporting Owners

Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
Zanco Joseph B C/O CATALYST BANCORP INC 235 N COURT ST OPELOUSAS, LA 70570	X		PRESIDENT AND CEO

Signatures

/s/ Jutta Codori by P.O.A. Joseph B. Zanco		06/11/2026
**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)	Represents the grant of shares pursuant to the Issuer's 2022 Recognition and Retention Plan and Trust Agreement that vest at 20% per year commencing on June 10, 2027.
(2)	Includes 8,464 shares granted pursuant to the Issuer's 2022 Recognition and Retention Plan and Trust Agreement that reflect the unvested portion of a grant amount originally covering 21,160 shares that commenced vesting 20% per year on September 1, 2023.
(3)	Includes 4,232 shares granted pursuant to the Issuer's 2022 Recognition and Retention Plan and Trust Agreement that reflect the unvested portion of a grant amount originally covering 5,290 shares that commenced vesting 20% per year on June 10, 2026.
(4)	Includes shares acquired in the Catalyst Bank 401(k) Plan since the last filed Form 4, based on a report dated June 4, 2026.
(5)	Includes shares allocated to the reporting person's account in the ESOP since the last filed Form 4, as of December 31, 2025.
(6)	These options are vesting at a rate of 20% per year that commenced on September 1, 2023.
(7)	These options are vesting at a rate of 20% per year that commenced on June 10, 2026.
(8)	These options vest at a rate of 20% per year commencing on June 10, 2027.

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