Fairmount Funds Management LLC - 22 Jan 2026 Form 4 Insider Report for Cogent Biosciences, Inc. (COGT)

Role: Director
Signature: /s/ Tomas Kiselak for Fairmount Funds Management LLC
Issuer symbol: COGT
Transactions as of: 22 Jan 2026
Net transactions value: -$127,400,000
Form type: 4
Filing time: 22 Jan 2026, 20:09:39 UTC
Previous filing: 08 Dec 2025
Next filing: 12 Feb 2026
SEC: View on sec.gov

Reporting Owners (1)

Name	Relationship	Address	Signature	Signature date	CIK
Fairmount Funds Management LLC	Director	200 BARR HARBOR DRIVE, SUITE 400, WEST CONSHOHOCKEN	/s/ Tomas Kiselak for Fairmount Funds Management LLC	22 Jan 2026	0001802528

Transactions Table

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Ownership	Footnotes
transaction	COGT	Common Stock	Sale	$127,400,000	-3,500,000	-39%	$36.40	5,503,418	22 Jan 2026	Fairmount Healthcare Fund II LP	F1

Derivative Securities (e.g., puts, calls, warrants, options, convertible securities)

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Underlying Class	Amount	Exercise Price	Ownership	Footnotes
holding	COGT	Series A Convertible Preferred Stock						67,414	22 Jan 2026	Common Stock	16,853,500		Fairmount Healthcare Fund II LP	F1, F2

* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Explanation of Responses:

Id	Content
F1	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.
F2	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.

Content

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.

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.

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.