Keros Therapeutics director granted RSUs and options

Keros Therapeutics director Alpna Seth received equity-based compensation rather than buying shares on the market.

Rhea-AI Filing Summary

Keros Therapeutics director Alpna Seth received equity-based compensation rather than buying shares on the market. On this Form 4, Seth was granted 7,142 restricted stock units of common stock and a stock option for 7,433 shares at an exercise price of $10.50 per share.

The RSUs vest in full on the earlier of June 3, 2027 or the company’s 2027 annual meeting of stockholders, as long as she continues providing service. The option vests in equal quarterly installments over 12 months following June 3, 2026, and will in any case be fully vested by the 2027 annual meeting, also subject to continued service. After these grants, she directly holds 12,392 common shares and 7,433 options.

Insider Trade Summary

Grant/Award: 14,575 shares

Grant/Award 2 txns

Insider Seth Alpna

Role Director

Type	Security	Shares	Price	Value
Grant/Award	Stock Option (right to buy)	7,433	$0.00	$0.00
Grant/Award	Common Stock	7,142	$0.00	$0.00

Holdings After Transaction: Stock Option (right to buy) — 7,433 contracts (Direct); Common Stock — 12,392 shares (Direct)

Footnotes (2)

1. F1. Represents a restricted stock unit ("RSU") award. The RSUs fully vest on the earlier of (A) June 3, 2027 and (B) the date of the Issuer's 2027 annual meeting of stockholders, subject to the Reporting Person continuing to provide service through each such date.
2. F2. The option shall vest in equal quarterly installments over the 12 months following June 3, 2026, provided that the grant will in any case be fully vested on the date of Issuer's 2027 annual meeting of stockholders, subject to the Reporting Person continuing to provide service through each such date.

Key Figures

RSU grant size: 7,142 units Option grant size: 7,433 options Option exercise price: $10.50 per share +3 more

6 metrics

RSU grant size 7,142 units Restricted stock unit award vesting by 2027 meeting

Option grant size 7,433 options Stock option for common stock granted to director

Option exercise price $10.50 per share Conversion or exercise price for stock option

Shares held after grant 12,392 shares Common stock directly owned following RSU grant

Options held after grant 7,433 options Total option position following this award

Option expiration June 2, 2036 Expiration date of the granted stock option

Key Terms

restricted stock unit ("RSU"), Stock Option (right to buy), annual meeting of stockholders, vest in equal quarterly installments

4 terms

restricted stock unit ("RSU") financial

"Represents a restricted stock unit ("RSU") award. The RSUs fully vest..."

Stock Option (right to buy) financial

"Stock Option (right to buy) with an exercise price of 10.5000..."

annual meeting of stockholders financial

"the date of the Issuer's 2027 annual meeting of stockholders, subject to..."

vest in equal quarterly installments financial

"The option shall vest in equal quarterly installments over the 12 months..."

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What did Alpna Seth acquire in this Keros Therapeutics (KROS) Form 4 filing?

Alpna Seth received equity compensation, not open-market purchases. She was granted 7,142 restricted stock units of common stock and a stock option covering 7,433 shares at a $10.50 exercise price, reflecting a standard director incentive package tied to future service requirements.

How many Keros Therapeutics (KROS) shares does Alpna Seth hold after these grants?

Following these transactions, Alpna Seth directly holds 12,392 shares of Keros Therapeutics common stock, plus a stock option for 7,433 additional shares. These holdings combine existing shares and the newly granted restricted stock units and options reported in this compensation-related Form 4 filing.

What are the vesting terms of Alpna Seth’s Keros Therapeutics RSU grant?

The 7,142 restricted stock units fully vest on the earlier of June 3, 2027 or the Keros Therapeutics 2027 annual meeting of stockholders. Vesting is conditional on Alpna Seth continuing to provide service to the company through whichever of these two dates occurs first.

How do Alpna Seth’s Keros Therapeutics stock options vest and when do they expire?

The 7,433-share stock option vests in equal quarterly installments over 12 months following June 3, 2026 and will be fully vested by the 2027 annual meeting, subject to continued service. The option expires on June 2, 2036 if not exercised before that date.

Was Alpna Seth buying Keros Therapeutics (KROS) shares on the open market in this Form 4?

No, the Form 4 reports compensation-related grants, not open-market buying. Alpna Seth received 7,142 restricted stock units and 7,433 stock options at a $10.50 strike price, both tied to future service and vesting schedules rather than discretionary market purchases.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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

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

OMB APPROVAL

OMB Number:			3235-0287
Estimated average burden
hours per response:			0.5

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^*

Seth Alpna

(Last) (First) (Middle)

C/O KEROS THERAPEUTICS, INC.

1050 WALTHAM STREET, SUITE 302

(Street)

LEXINGTON MASSACHUSETTS 02421

(City) (State) (Zip)

UNITED STATES

(Country)

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)

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
06/03/2026

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

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

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

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	06/03/2026		A		7,142(1)	A	$0	12,392	D

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
Stock Option (right to buy)	$10.5	06/03/2026		A		7,433		(2)	06/02/2036	Common Stock	7,433	$0	7,433	D

Explanation of Responses:

1. Represents a restricted stock unit ("RSU") award. The RSUs fully vest on the earlier of (A) June 3, 2027 and (B) the date of the Issuer's 2027 annual meeting of stockholders, subject to the Reporting Person continuing to provide service through each such date.

2. The option shall vest in equal quarterly installments over the 12 months following June 3, 2026, provided that the grant will in any case be fully vested on the date of Issuer's 2027 annual meeting of stockholders, subject to the Reporting Person continuing to provide service through each such date.

	/s/ Esther Cho, Attorney-in-Fact	06/05/2026
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.
* Form 4: SEC 1474 (03-26)