Cogent Biosciences (NASDAQ: COGT) group reports 9,043,903 shares

Rhea-AI Filing Summary

Cogent Biosciences, Inc. Schedule 13G/A reports that Deerfield Mgmt, L.P., Deerfield Management Company, L.P., Deerfield Partners, L.P. and James E. Flynn each beneficially own 9,043,903 shares of common stock, representing 5.29% of the class as of 03/31/2026. The filing states these holdings are comprised of shares held by Deerfield Partners, L.P., with shared voting and dispositive power reported.

Key Figures

Shares beneficially owned: 9,043,903 shares Percent of class: 5.29% Filing type: Schedule 13G/A +3 more

6 metrics

Shares beneficially owned 9,043,903 shares Beneficially owned by each reporting person as reported

Percent of class 5.29% Percent of common stock as of 03/31/2026

Filing type Schedule 13G/A Ownership disclosure filing for passive/beneficial holders

CUSIP 19240Q201 Identifier for Cogent Biosciences common stock

Reporting period/date 03/31/2026 Date tied to ownership figures in the filing

Signature date 05/14/2026 Date signatures by Attorney-In-Fact were executed

Key Terms

Schedule 13G/A, beneficially own, shared dispositive power, joint filing agreement

4 terms

Schedule 13G/A regulatory

"Schedule 13G/A header indicating an amendment filing"

A Schedule 13G/A is an amended public filing with the U.S. securities regulator that updates a previous Schedule 13G, disclosing when an individual or group holds a substantial (typically over 5%) stake in a company and is claiming a passive, non‑controlling intent. Investors monitor these updates because rising or falling holdings can signal changing confidence, potential future moves, or shifts in voting power — like watching a public ledger where large shareholders quietly adjust their positions.

beneficially own financial

"Item 4. Ownership (a) Amount beneficially owned: Deerfield Mgmt, L.P. - 9,043,903 shares"

Beneficially own means having the economic rights and risks of a security—such as the right to receive dividends, sell the shares, or profit from price changes—whether or not your name appears on the official share register. Think of it like renting a car: you use it and reap the benefits even if the title lists someone else. Investors care because beneficial ownership determines who truly controls value, must be disclosed under securities rules, and can signal potential influence or trading activity that affects a stock’s price.

shared dispositive power regulatory

"Item 4. (iv) Shared power to dispose or to direct the disposition of: Deerfield Mgmt, L.P. - 9,043,903"

joint filing agreement regulatory

"Exhibit A. Joint Filing Agreement."

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Accepted by SEC EDGAR 05/14/2026 - 06:20 PM Learn about SEC filing dates

FAQ

What does Cogent Biosciences (COGT) Schedule 13G/A disclose?

It discloses that Deerfield-affiliated parties and James E. Flynn beneficially own 9,043,903 shares, or 5.29% of common stock as of 03/31/2026. The filing attributes the holdings to Deerfield Partners, L.P. with shared voting and dispositive power.

Who are the reporting parties in the COGT filing?

The reporting parties are Deerfield Mgmt, L.P., Deerfield Management Company, L.P., Deerfield Partners, L.P. and James E. Flynn, all listed with addresses and citizenship as shown in the filing.

How much of COGT does Deerfield control according to the filing?

Each reporting person is shown as beneficially owning 9,043,903 shares, equal to 5.29% of the class as reported on 03/31/2026. The filing shows shared voting and dispositive power for that share count.

Does the Schedule 13G/A indicate whether the shares are directly held or through entities?

The filing states the holdings are comprised of shares held by Deerfield Partners, L.P., with Deerfield Mgmt and Deerfield Management Company identified as general partner and investment advisor respectively.

When was the Schedule 13G/A signed and who signed it for the reporting parties?

The document bears signatures executed by Jonathan Isler, Attorney-In-Fact on behalf of the reporting persons, dated 05/14/2026, as shown in the filing's signature blocks.

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

(Amendment No. 1)

Cogent Biosciences, Inc.

(Name of Issuer)

Common Stock

(Title of Class of Securities)

19240Q201

(CUSIP Number)

03/31/2026

(Date of Event Which Requires Filing of this Statement)

Check the appropriate box to designate the rule pursuant to which this Schedule is filed:

Rule 13d-1(b)

Rule 13d-1(c)

Rule 13d-1(d)

schemaVersion:

SCHEDULE 13G

CUSIP Number(s): 19240Q201

1

Names of Reporting Persons

Deerfield Mgmt, L.P.

2

Check the appropriate box if a member of a Group (see instructions)

(a)
(b)

3

Sec Use Only

4

Citizenship or Place of Organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 9,043,903.00
6	Shared Voting Power 0.00
7	Sole Dispositive Power 9,043,903.00
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

9,043,903.00

10

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

11

Percent of class represented by amount in row (9)

5.29 %

12

Type of Reporting Person (See Instructions)

PN

Comment for Type of Reporting Person: Comprised of shares of common stock held by Deerfield Partners, L.P., of which Deerfield Mgmt, L.P. is the general partner.

SCHEDULE 13G

CUSIP Number(s): 19240Q201

1

Names of Reporting Persons

Deerfield Management Company, L.P.

2

Check the appropriate box if a member of a Group (see instructions)

(a)
(b)

3

Sec Use Only

4

Citizenship or Place of Organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 9,043,903.00
6	Shared Voting Power 0.00
7	Sole Dispositive Power 9,043,903.00
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

9,043,903.00

10

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

11

Percent of class represented by amount in row (9)

5.29 %

12

Type of Reporting Person (See Instructions)

PN

Comment for Type of Reporting Person: Comprised of shares of common stock held by Deerfield Partners, L.P. of which Deerfield Management Company, L.P. is the investment advisor.

SCHEDULE 13G

CUSIP Number(s): 19240Q201

1

Names of Reporting Persons

Deerfield Partners, L.P.

2

Check the appropriate box if a member of a Group (see instructions)

(a)
(b)

3

Sec Use Only

4

Citizenship or Place of Organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 9,043,903.00
6	Shared Voting Power 0.00
7	Sole Dispositive Power 9,043,903.00
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

9,043,903.00

10

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

11

Percent of class represented by amount in row (9)

5.29 %

12

Type of Reporting Person (See Instructions)

PN

SCHEDULE 13G

CUSIP Number(s): 19240Q201

1

Names of Reporting Persons

James E. Flynn

2

Check the appropriate box if a member of a Group (see instructions)

(a)
(b)

3

Sec Use Only

4

Citizenship or Place of Organization

UNITED STATES

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 9,043,903.00
6	Shared Voting Power 0.00
7	Sole Dispositive Power 9,043,903.00
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

9,043,903.00

10

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

11

Percent of class represented by amount in row (9)

5.29 %

12

Type of Reporting Person (See Instructions)

IN

Comment for Type of Reporting Person: Comprised of shares of common stock held by Deerfield Partners, L.P.

SCHEDULE 13G

Item 1.
(a)	Name of issuer: Cogent Biosciences, Inc.
(b)	Address of issuer's principal executive offices: 275 Wyman Street, 3rd Floor, Waltham, Massachusetts 02451
Item 2.
(a)	Name of person filing: James E. Flynn, Deerfield Mgmt, L.P., Deerfield Management Company, L.P. and Deerfield Partners, L.P.
(b)	Address or principal business office or, if none, residence: James E. Flynn, Deerfield Mgmt, L.P., Deerfield Management Company, L.P. and Deerfield Partners, L.P., 345 Park Avenue South, 12th Floor, New York, NY 10010
(c)	Citizenship: Deerfield Mgmt, L.P., Deerfield Management Company, L.P. and Deerfield Partners, L.P. - Delaware limited partnerships; James E. Flynn - United States citizen
(d)	Title of class of securities: Common Stock
(e)	CUSIP No.: 19240Q201
Item 3.	If this statement is filed pursuant to §§ 240.13d-1(b) or 240.13d-2(b) or (c), check whether the person filing is a:
(a)	Broker or dealer registered under section 15 of the Act (15 U.S.C. 78o);
(b)	Bank as defined in section 3(a)(6) of the Act (15 U.S.C. 78c);
(c)	Insurance company as defined in section 3(a)(19) of the Act (15 U.S.C. 78c);
(d)	Investment company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8);
(e)	An investment adviser in accordance with § 240.13d-1(b)(1)(ii)(E);
(f)	An employee benefit plan or endowment fund in accordance with § 240.13d-1(b)(1)(ii)(F);
(g)	A parent holding company or control person in accordance with § 240.13d-1(b)(1)(ii)(G);
(h)	A savings associations as defined in Section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813);
(i)	A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the Investment Company Act of 1940 (15 U.S.C. 80a-3);
(j)	A non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J). If filing as a non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J), please specify the type of institution:
(k)	Group, in accordance with Rule 240.13d-1(b)(1)(ii)(K).
Item 4.	Ownership
(a)	Amount beneficially owned: Deerfield Mgmt, L.P. - 9,043,903 shares Deerfield Management Company, L.P. - 9,043,903 shares Deerfield Partners, L.P. - 9,043,903 shares James E. Flynn - 9,043,903 shares
(b)	Percent of class: Deerfield Mgmt, L.P. - 5.29% Deerfield Management Company, L.P. - 5.29% Deerfield Partners, L.P. - 5.29% James E. Flynn - 5.29%
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: All Reporting Persons - 0
	(ii) Shared power to vote or to direct the vote: Deerfield Mgmt, L.P. - 9,043,903 Deerfield Management Company, L.P. - 9,043,903 Deerfield Partners, L.P. - 9,043,903 James E. Flynn - 9,043,903
	(iii) Sole power to dispose or to direct the disposition of: All Reporting Persons - 0
	(iv) Shared power to dispose or to direct the disposition of: Deerfield Mgmt, L.P. - 9,043,903 Deerfield Management Company, L.P. - 9,043,903 Deerfield Partners, L.P. - 9,043,903 James E. Flynn - 9,043,903
Item 5.	Ownership of 5 Percent or Less of a Class.
	Not Applicable
Item 6.	Ownership of more than 5 Percent on Behalf of Another Person.
	Not Applicable
Item 7.	Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on by the Parent Holding Company or Control Person.
	Not Applicable
Item 8.	Identification and Classification of Members of the Group.
	If a group has filed this schedule pursuant to §240.13d-1(b)(1)(ii)(J), so indicate under Item 3(j) and attach an exhibit stating the identity and Item 3 classification of each member of the group. If a group has filed this schedule pursuant to §240.13d-1(c) or §240.13d-1(d), attach an exhibit stating the identity of each member of the group. See Exhibit B
Item 9.	Notice of Dissolution of Group.
	Not Applicable

Item 10.

Certifications:

By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect, other than activities solely in connection with a nomination under ?? 240.14a-11.

SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

Deerfield Mgmt, L.P.

Signature:	/s/ Jonathan Isler
Name/Title:	Jonathan Isler, Attorney-In-Fact
Date:	05/14/2026

Deerfield Management Company, L.P.

Signature:	/s/ Jonathan Isler
Name/Title:	Jonathan Isler, Attorney-In-Fact
Date:	05/14/2026

Deerfield Partners, L.P.

Signature:	/s/ Jonathan Isler
Name/Title:	Jonathan Isler, Attorney-In-Fact
Date:	05/14/2026

James E. Flynn

Signature:	/s/ Jonathan Isler
Name/Title:	Jonathan Isler, Attorney-In-Fact
Date:	05/14/2026

Exhibit Information

Exhibit A. Joint Filing Agreement. Exhibit B. Item 8 Statement. Exhibit C. Power of Attorney (1). (1) Power of Attorney previously filed as Exhibit 24 to a Form 3 with regard to BiomX Inc. filed with the Securities and Exchange Commission on March 19, 2024 by Deerfield Private Design Fund V, L.P., Deerfield Healthcare Innovations Fund II, L.P., Deerfield Mgmt V, L.P., Deerfield Mgmt HIF II, L.P., Deerfield Management Company, L.P. and James E. Flynn.