Rhonda M. Chicko - 14 Aug 2026 Form 4 Insider Report for Cyclerion Therapeutics, Inc. (CYCN)

Reporting relationship: Chief Financial Officer
Issuer ticker: CYCN
Reported as of: 14 Aug 2026
Net transaction value: $0
SEC form: 4
Accepted by SEC: 18 Aug 2026, 17:27:18 UTC
Prior SEC filing: 11 Aug 2025
Source filing: View source filing
Reporting owner signature: /s/ Rhonda Chicko

Key filing fact

Rhonda M. Chicko filed Form 4 for Cyclerion Therapeutics, Inc. (CYCN) on 18 Aug 2026.

Key facts

This page summarizes Rhonda M. Chicko's Form 4 filing for Cyclerion Therapeutics, Inc. (CYCN).
2 reported transactions and 1 derivative row are listed below.
Accepted by SEC: 18 Aug 2026, 17:27.

Change

Previous filing in this sequence was filed on 11 Aug 2025.
Current net transaction value: $0.

Research use

This tells you what this filing adds before you inspect full transaction and derivative tables.
You can trace every row back to the original SEC filing document.

Evidence

Filed on Form 4

Ownership activity is grounded in SEC Form 4 disclosures.

View source filing

Reporting Owners (1)

CIK 0001740376 Primary reporting owner

CHICKO RHONDA M.

Relationship: Chief Financial Officer
Address: C/O CYCLERION THERAPEUTICS, INC., 245 FIRST STREET, 18TH FLOOR, CAMBRIDGE
Signature: /s/ Rhonda Chicko
Signature date: 18 Aug 2026

Reported non-derivative transactions

Shares, units, or other non-derivative securities reported in this filing.

CYCN transaction

Common Stock, no par value

Options Exercise

Transaction value
Shares: +25,000
Change %: +138889%
Price: $2.36^*
Shares after: 25,018
Date: 14 Aug 2026
Ownership: Direct
Footnotes: F1

Reported derivative securities

Options, warrants, convertible securities, or similar derivative positions disclosed in the filing.

CYCN transaction Derivative

Option to Purchase

Options Exercise

Transaction value
Shares: -25,000
Change %: -100%
Price: $0.000000^*
Shares after: 0
Date: 14 Aug 2026
Ownership: Direct
Underlying class: Common Stock
Underlying amount: 25,000
Exercise price: $2.36
Footnotes: F1

^* marks a reported price that did not pass the local price check.

Additional SEC filing notes

Filing notes and footnotes

Explanation of responses 1 footnote

Footnote F1

The Reporting Person was granted an option on August 7, 2025 to purchase up to 25,000 shares of the Corporation's common stock pursuant to the Issuer's 2019 Equity Incentive Plan. These 25,000 shares provided for vesting as follows: (i) 8,750 shares became immediately exercisable, and (ii) the remaining 16,250 shares were to vest ratably in monthly installments commencing August 31, 2025 and ending on February 28, 2028, provided that the Reporting Person remained as a consultant or employee of 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 for the Reporting Person. The Reporting Person exercised the option in full on August 14, 2026 and paid for the exercise by means of a cash payment to the Issuer for the full purchase price.