Keros Therapeutics (NASDAQ: KROS) OrbiMed-linked funds report tender offer sale

Rhea-AI Filing Summary

Keros Therapeutics, Inc. director-affiliated investment entities reported selling common stock in connection with the company’s completion of a cash tender offer. OrbiMed-related funds disposed of 140,057 shares and 74,465 shares of Keros common stock at a price of $17.75 per share on 11/21/2025. Following these transactions, one OrbiMed fund reported indirect beneficial ownership of 759,155 shares, and another reported 45,057 shares, while the reporting entities each disclaim beneficial ownership beyond their pecuniary interest.

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

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Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

ORBIMED ADVISORS LLC

(Last) (First) (Middle)

601 LEXINGTON AVENUE

54TH FLOOR

(Street)

NEW YORK NY 10022

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
Keros Therapeutics, Inc. [ KROS ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

X	Director		10% Owner
	Officer (give title below)		Other (specify below)

3. Date of Earliest Transaction (Month/Day/Year)
11/21/2025

4. If Amendment, Date of Original Filed (Month/Day/Year)

6. Individual or Joint/Group Filing (Check Applicable Line)

	Form filed by One Reporting Person
X	Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Stock	11/21/2025		D(1)		140,057	D	$17.75	759,155	I	See footnotes(2)(4)
Common Stock	11/21/2025		D(1)		74,465	D	$17.75	45,057	I	See footnotes(3)(4)

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares

1. Name and Address of Reporting Person^*

ORBIMED ADVISORS LLC

(Last) (First) (Middle)

601 LEXINGTON AVENUE

54TH FLOOR

(Street)

NEW YORK NY 10022

(City) (State) (Zip)

Relationship of Reporting Person(s) to Issuer

X	Director		10% Owner
	Officer (give title below)		Other (specify below)

1. Name and Address of Reporting Person^*

OrbiMed Capital GP VII LLC

(Last) (First) (Middle)

601 LEXINGTON AVENUE, 54TH FLOOR

(Street)

NEW YORK NY 10022

(City) (State) (Zip)

Relationship of Reporting Person(s) to Issuer

X	Director		10% Owner
	Officer (give title below)		Other (specify below)

1. Name and Address of Reporting Person^*

OrbiMed Genesis GP LLC

(Last) (First) (Middle)

601 LEXINGTON AVENUE, 54TH FLOOR

(Street)

NEW YORK NY 10022

(City) (State) (Zip)

Relationship of Reporting Person(s) to Issuer

X	Director		10% Owner
	Officer (give title below)		Other (specify below)

Explanation of Responses:

1. Disposed of in connection with the Issuer's completion of a cash tender offer.

2. These securities are held of record by OrbiMed Private Investments VII, LP ("OPI VII"). OrbiMed Capital GP VII LLC ("OrbiMed GP") is the general partner of OPI VII and OrbiMed Advisors LLC ("OrbiMed Advisors") is the managing member of OrbiMed GP. By virtue of such relationships, OrbiMed GP and OrbiMed Advisors may be deemed to have voting power and investment power over the securities held by OPI VII and as a result, may be deemed to have beneficial ownership over such securities. OrbiMed Advisors exercises voting and investment power through a management committee comprised of Carl L. Gordon, Sven H. Borho, and W. Carter Neild, each of whom disclaims beneficial ownership of the shares held by OPI VII.

3. These securities are held of record by OrbiMed Genesis Master Fund, L.P. ("Genesis"). OrbiMed Genesis GP LLC ("Genesis GP") is the general partner of Genesis and OrbiMed Advisors is the managing member of Genesis GP. By virtue of such relationships, Genesis GP and OrbiMed Advisors may be deemed to have voting power and investment power over the securities held by Genesis and as a result, may be deemed to have beneficial ownership over such securities. OrbiMed Advisors exercises voting and investment power through a management committee comprised of Carl L. Gordon, Sven H. Borho, and W. Carter Neild, each of whom disclaims beneficial ownership of the shares held by Genesis.

4. This report on Form 4 is jointly filed by OrbiMed Advisors, OrbiMed GP, and Genesis GP. Each of the Reporting Persons disclaims beneficial ownership of the securities reported herein for purposes of Rule 16a-1(a) under the Securities Exchange Act of 1934, as amended (the "Exchange Act"), except to the extent of its pecuniary interest therein, if any. The Reporting Persons have designated a representative, Carl L. Gordon, a member of OrbiMed Advisors, to serve on the Issuer's board of directors. This report shall not be deemed an admission that any such entity or person is a beneficial owner of such securities for purposes of Section 16 of the Exchange Act, or for any other purpose.

	/s/ Carl L. Gordon, Member of OrbiMed Advisors LLC	12/18/2025
	/s/ Carl L. Gordon, Member of OrbiMed Capital GP VII LLC	12/18/2025
	/s/ Carl L. Gordon, Member of OrbiMed Genesis GP LLC	12/18/2025
	** Signature of Reporting Person	Date
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FAQ

What insider transaction did Keros Therapeutics (KROS) report?

The filing reports that OrbiMed-affiliated entities, which have a representative on Keros Therapeutics’ board, disposed of common stock as part of a completed cash tender offer.

How many Keros Therapeutics (KROS) shares were sold and at what price?

The reporting entities disposed of 140,057 shares and 74,465 shares of Keros Therapeutics common stock at a price of $17.75 per share on 11/21/2025.

How many Keros Therapeutics (KROS) shares do the reporting persons hold after the transactions?

After the reported transactions, one OrbiMed-related fund reported indirect beneficial ownership of 759,155 Keros common shares and another reported 45,057 shares.

Who are the reporting persons in this Keros Therapeutics (KROS) Form 4?

The reporting persons are OrbiMed Private Investments VII, LP, OrbiMed Genesis Master Fund, L.P., and related entities including OrbiMed Capital GP VII LLC, OrbiMed Genesis GP LLC, and OrbiMed Advisors LLC, with Carl L. Gordon signing as a member of these entities.

What is the relationship of the reporting persons to Keros Therapeutics (KROS)?

The reporting persons are indicated as having a director relationship to Keros Therapeutics through a designated representative, Carl L. Gordon, who serves on the company’s board of directors.

Why do the reporting persons disclaim beneficial ownership of Keros Therapeutics (KROS) shares?

The entities state that they may be deemed to have voting and investment power over the shares through their roles with the funds, but disclaim beneficial ownership except to the extent of their pecuniary interest, and clarify that this report should not be deemed an admission of beneficial ownership.