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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(Print or Type Responses)

1. Name and Address of Reporting Person * Graul Regina Margaret 2. Issuer Name and Ticker or Trading Symbol Cyclerion Therapeutics, Inc. [CYCN] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) __X__ Director _____ 10% Owner __X__ Officer (give title below) _____ Other (specify below) See Remarks (Last) (First) (Middle) C/O CYCLERION THERAPEUTICS, INC., 245 FIRST STREET, 18TH FLOOR 3. Date of Earliest Transaction (Month/Day/Year) 08/14/2026 (Street) CAMBRIDGE, MA 02142 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, no par value 08/14/2026 M(1) 55,849 A $3.3 156,152 D Common Stock, no par value 08/14/2026 F(2) 48,629 D $3.79 107,523 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

Option to Purchase

$3.3

08/14/2026

M(1)

55,849

(1)

08/03/2034

Common Stock

55,849

$ 0

0

D

Reporting Owners

Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
Graul Regina Margaret C/O CYCLERION THERAPEUTICS, INC. 245 FIRST STREET, 18TH FLOOR CAMBRIDGE, MA 02142	X		See Remarks

Signatures

/s/ Regina Margaret Graul		08/18/2026
**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)	The Reporting Person was granted an option on August 5, 2024 to purchase up to 55,849 shares of the Corporation's common stock pursuant to the 2019 Equity Incentive Plan, vesting ratably in monthly installments over a 48-month period commencing August 31, 2024 and ending July 31, 2028, provided that the Reporting Person remained employed by Cyclerion Therapeutics, Inc. on such applicable vesting date, subject to certain exemptions. On July 17, 2026, the Issuer's Board of Directors elected to accelerate in full the vesting of all then unvested options and all then unvested restricted shares for the Reporting Person.
(2)	The Reporting Person exercised the option in full on August 14, 2026 and paid for the exercise by means of a cashless exercise, forfeiting options to purchase 48,629 shares as payment to the Issuer for the full exercise price.
Remarks: President and Chief Executive Officer

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