SEC ownership of Cyclerion Therapeutics, Inc.

Top holders, 13D/G large-stake signals, insider positions, and transaction flow tied to CIK 0001755237.

Comparable stake leader

Peter M. Hecht

Disclosed value leader

Peter M. Hecht

Comparable rows

21/37

Latest evidence

31 Mar 2026

Top shareholders Insider holders Latest transactions
Public ticker
CYCN on Nasdaq
Parsed ownership sources
13D/G, 3/4/5, and 13F
Source: Parsed SEC ownership filingsUse: Compare filing families carefully
Largest SEC-reported holder
Peter M. Hecht
Ranking: Comparable ownership first, then disclosed value
Ownership snapshot CIK-linked ownership evidence from parsed SEC filings. 3 signals
Comparable ownership rows
21 of 37
Meaning: Rows with safely comparable ownership %
Latest 13D/G holder
Peter M. Hecht
Source: Latest parsed Schedule 13D/G stake
Latest parsed ownership date
31 Mar 2026
Freshness: Most recent filing date in this holder set
Issuer Names, identifiers, and filing context for this profile. 2 identity fields
Issuer CIK
0001755237
Issuer location
Cambridge, MA

Ownership snapshot

Top shareholders of Cyclerion Therapeutics, Inc. (13F + 13D/G + 3/4/5)

Grouped by holder across the latest SEC ownership disclosures. Start with comparable ownership when available, then verify the linked 13F, 13D/G, or 3/4/5 evidence.

Comparable stake leader
Peter M. Hecht
Disclosed value leader
Peter M. Hecht
Comparable rows
21/37
Latest evidence
31 Mar 2026
13D/G 3/4/5 13F Lead comparable stake: 28% 16 rows are not safely comparable across share classes. 13D/G row: Peter M. Hecht Showing 1-8 of 37 holder rows.

Quick read

Peter M. Hecht leads the comparable SEC ownership view at 28%.

21 of 37 rows have a safely comparable ownership percentage. Use this as a filing-backed starting point, then open the detailed table for source links, reporting role, position value, share count, and filing date.

Open SEC evidence Opens Peter M. Hecht's linked filing trail.
Comparable ownership Top 5
Peter M. Hecht 28%
FMR LLC 15%
J. WOOD CAPITAL ADVISORS LLC 5.4%
American Endowment Foundation 4.9%
TYNDALL CAPITAL PARTNERS L P 4.8%

Ownership % is shown only when SEC disclosures are safely comparable across share classes.

Detailed SEC evidence table Showing 1-8 of 37 holder rows
Holder Evidence Ownership % Position 12M Net Δ As of
Peter M. Hecht
13D/G 3/4/5
Director, 10%+ Owner
13D/G 3/4/5
28%
$3,803,918
1,028,086 shares
 $0 25 Mar 2025
FMR LLC
13F 13D/G
Company
13F 13D/G
15%
from 13D/G
$7,276
4,740 shares
 — 31 Mar 2026
J. WOOD CAPITAL ADVISORS LLC
13D/G
13D/G
5.4%
$496,363
181,818 shares
 $0 25 Mar 2025
American Endowment Foundation
13D/G
13D/G
4.9%
$492,196
133,026 shares
 $0 31 Dec 2024
TYNDALL CAPITAL PARTNERS L P
13D/G
13D/G
4.8%
$487,287
155,187 shares
 -$30,113 30 Jun 2025
GEODE CAPITAL MANAGEMENT, LLC
13F
Company
13F
2.5%
$129,800
84,550 shares
 — 31 Mar 2026
CITADEL ADVISORS LLC
13F
Company
13F
0.54%
$28,031
18,261 shares
 — 31 Mar 2026
BlackRock, Inc.
13F
Company
13F
0.5%
$26,035
16,797 shares
 — 31 Mar 2026
How to read this table

Rows are grouped by holder and ranked first by SEC-reported ownership % when it is safely comparable, then by disclosed holdings value. — indicates unavailable or non-comparable values; "mixed-class rows" means the latest filing spans non-comparable classes.

Forms 3/4/5 flow

Insider trading overview

Insider buy and sell flow is broadly balanced over the last 12 months. No Buy or Sell transactions have been reported since 27 Jun 2025.

Buys
$0
Insiders: 0
Sells
$0
Insiders: 0
Net
$0
Shares: 0
Window
Last 12 months
4 rolling buckets
Buy value Sell value
Shares: 0 Shares: 0
Window (months) Buy shares Sell shares Buy value Sell value Net value
0-3 0 0 $0 $0 $0
3-6 0 0 $0 $0 $0
6-9 0 0 $0 $0 $0
9-12 0 0 $0 $0 $0

Reporting owners

Insider holders from Forms 3/4/5

Showing 1-18 of 18 reporting-owner rows connected to Cyclerion Therapeutics, Inc.. Open a relationship link for the CIK-to-CIK filing trail.

Rows
18
Largest Forms 3/4/5 holder
Peter M. Hecht
Net 12M change
$0
Latest report
07 Aug 2025
Name Relationship Holdings Value Past Year Net Change Change % Valuation Report Date
Peter M. Hecht Director, 10%+ Owner $1,538,006 Mixed 25 Mar 2025
Regina M. Graul President and Chief Executive Officer, Director $340,529 Mixed 05 Aug 2024
Terrance McGuire Director $142,624 Mixed 30 Nov 2023
Errol B. Desouza Director $101,850 Mixed 30 Nov 2023
Michael J. Higgins Director $84,535 Mixed 25 Mar 2025
Steven Hyman Director $67,900 Mixed 30 Nov 2023
Dina Katabi Director $67,900 Mixed 30 Nov 2023
Slate Path Capital LP 10%+ Owner $0 Mixed 21 Nov 2024
Stephanie Lovell Director Mixed 14 Jun 2022
Andreas Busch Chief Scientific Officer Mixed 20 Jan 2022
Kevin Churchwell Director Mixed 24 Jun 2021
Ole Isacson Director Mixed 14 Jun 2022
George H. Conrades Director Mixed 14 Jun 2022
Cheryl Gault Chief Operating Officer Mixed 20 Jan 2022
Rhonda M. Chicko Chief Financial Officer Mixed 07 Aug 2025
Michael Mendelsohn Director Mixed 14 Jun 2022
Anjeza Gjino Chief Financial Officer Mixed 20 Jan 2022
Marsha Fanucci Director Mixed 14 Jun 2022

Recent insider transactions for Cyclerion Therapeutics, Inc.

Showing up to 300 recent insider transactions from the last 12 months.

Insider Symbol Class Transaction % SEC-reported value SEC-reported price Shares Shares owned Date Ownership
Rhonda M. Chicko CYCN Stock Option (Right to Buy) Award 25,000 25,000 07 Aug 2025 Direct
* marks a reported price that did not pass the local price check.
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