Fairmount Funds Management LLC - 31 Mar 2026 Form 4 Insider Report for Cogent Biosciences, Inc. (COGT)

Reporting relationship: Director
Issuer ticker: COGT
Reported as of: 31 Mar 2026
Net transaction value: -$242,620,000
SEC form: 4
Accepted by SEC: 31 Mar 2026, 21:30:12 UTC
Prior SEC filing: 25 Mar 2026
Next SEC filing: 13 May 2026
Source filing: View source filing
Reporting owner signature: /s/ Tomas Kiselak for Fairmount Funds Management LLC

Key filing fact

Fairmount Funds Management LLC filed Form 4 for Cogent Biosciences, Inc. (COGT) on 31 Mar 2026.

Key facts

This page summarizes Fairmount Funds Management LLC's Form 4 filing for Cogent Biosciences, Inc. (COGT).
3 reported transactions and 1 derivative row are listed below.
Accepted by SEC: 31 Mar 2026, 21:30.

Change

Previous filing in this sequence was filed on 25 Mar 2026.
Current net transaction value: -$242,620,000.

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 0001802528 Primary reporting owner

Fairmount Funds Management LLC

Relationship: Director
Address: 200 BARR HARBOR DRIVE, SUITE 400, WEST CONSHOHOCKEN
Signature: /s/ Tomas Kiselak for Fairmount Funds Management LLC
Signature date: 31 Mar 2026

Reported non-derivative transactions

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

COGT transaction

Common Stock

Conversion of derivative security

Transaction value
Shares: +7,000,000
Change %: +127%
Price
Shares after: 12,503,418
Date: 31 Mar 2026
Ownership: Fairmount Healthcare Fund II LP
Footnotes: F1, F2

COGT transaction

Common Stock

Sale

Transaction value: $242,620,000
Shares: -7,000,000
Change %: -56%
Price: $34.66
Shares after: 5,503,418
Date: 31 Mar 2026
Ownership: Fairmount Healthcare Fund II LP
Footnotes: F2

Reported derivative securities

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

COGT transaction Derivative

Series A Convertible Preferred Stock

Conversion of derivative security

Transaction value
Shares: -28,000
Change %: -42%
Price: $0.000000^*
Shares after: 39,414
Date: 31 Mar 2026
Ownership: Fairmount Healthcare Fund II LP
Underlying class: Common Stock
Underlying amount: 7,000,000
Exercise price
Footnotes: F1, F2

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

Additional SEC filing notes

Filing notes and footnotes

Explanation of responses 2 footnotes

Footnote F1

Each share of Series A Convertible Preferred Stock is convertible into shares of Common Stock at any time at the option of the holder thereof, into 250 shares of Common Stock, subject to certain limitations, including that a holder of Series A Preferred Stock is prohibited from converting shares of Series A Preferred Stock into shares of Common Stock if, as a result of such conversion, such holder, together with its affiliates, would beneficially own more than 9.9% of the total number of shares of Common Stock issued and outstanding immediately after giving effect to such conversion. On March 31, 2026, the Reporting Persons converted 28,000 shares of Series A Convertible Preferred Stock into 7,000,000 shares of Common Stock for no cash consideration, in accordance with the Certificate of Designations for the Series A Convertible Preferred Stock.

Footnote F2

Fairmount Funds Management LLC and Fairmount Healthcare Fund II GP LLC have voting power and investment power over the securities held by Fairmount Healthcare Fund II LP ("Fund II"). They disclaim beneficial ownership of securities held by Fund II for purposes of Rule 16a-1(a)(2), except to the extent of their pecuniary interest therein.

SEC remarks

This Form 4 is filed jointly with Fairmount Healthcare Fund II GP LLC. The Reporting Person may be deemed a director by deputization of Issuer by virtue of the fact that Peter Harwin serves on the board of directors of Issuer and is also a Managing Member of Fairmount Funds Management LLC.