Keros director granted RSUs and options

Keros Therapeutics director Anne Prener received new equity awards.

Rhea-AI Filing Summary

Keros Therapeutics director Anne Prener received new equity awards. On July 1, 2026, she was granted 13,786 shares of Common Stock as restricted stock units (RSUs), with no cash paid per share. These RSUs vest over three years in twelve equal quarterly installments starting August 15, 2026, if she remains in continuous service.

On the same date, she was also granted a stock option for 14,870 shares of Common Stock at an exercise price of $10.88 per share, expiring on June 30, 2036. This option vests in equal quarterly installments over three years beginning October 1, 2026, also conditioned on continued service. The filing shows no open-market buying or selling; these are compensation-related grants.

Insider Trade Summary

Grant/Award: 28,656 shares

Grant/Award 2 txns

Insider Prener Anne

Role Director

Type	Security	Shares	Price	Value
Grant/Award	Stock Option (right to buy)	14,870	$0.00	$0.00
Grant/Award	Common Stock	13,786	$0.00	$0.00

Holdings After Transaction: Stock Option (right to buy) — 14,870 contracts (Direct); Common Stock — 13,786 shares (Direct)

Footnotes (2)

1. F1. Represents a restricted stock unit ("RSU") award. The RSUs shall vest over a three-year period in twelve equal quarterly installments with the first such vesting to occur on August 15, 2026, subject to the Reporting Person's continuous service through each such vesting date.
2. F2. The shares subject to the option shall vest over a three-year period in equal quarterly installments with the first such vesting to occur on October 1, 2026, subject to the Reporting Person's continuous service through each such vesting date.

Key Figures

RSU grant size: 13,786 shares RSU vesting start: August 15, 2026 Option grant size: 14,870 shares +5 more

8 metrics

RSU grant size 13,786 shares Restricted stock unit award granted July 1, 2026

RSU vesting start August 15, 2026 First of twelve equal quarterly RSU vesting dates

Option grant size 14,870 shares Stock option covering common stock granted July 1, 2026

Option exercise price $10.88 per share Stock option strike price for 14,870 shares

Option vesting start October 1, 2026 First quarterly vesting date for stock option

Option expiration June 30, 2036 Expiration date of stock option grant

Shares after RSU transaction 13,786 shares Total common stock reported following RSU transaction

Derivative shares after option grant 14,870 shares Total option shares reported following derivative transaction

Key Terms

restricted stock unit ("RSU") award, stock option (right to buy), vesting, continuous service

4 terms

restricted stock unit ("RSU") award financial

"Represents a restricted stock unit ("RSU") award. The RSUs shall vest over a three-year period in twelve equal quarterly installments"

stock option (right to buy) financial

"Stock Option (right to buy) with an exercise price of 10.8800 and expiration date June 30, 2036"

vesting financial

"The RSUs shall vest over a three-year period in twelve equal quarterly installments with the first such vesting to occur on August 15, 2026"

Vesting is the process by which you earn full ownership of something, like company stock or a retirement benefit, over time. It’s like earning the right to keep a gift piece by piece the longer you stay with a company, making sure employees stay committed before they receive all the benefits.

continuous service financial

"subject to the Reporting Person's continuous service through each such vesting date"

FAQ

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

What equity awards did Anne Prener receive from Keros Therapeutics (KROS)?

Anne Prener received a grant of 13,786 restricted stock units and a stock option for 14,870 shares. Both awards are compensation-related and were granted on July 1, 2026, with multi-year vesting schedules tied to continued service on the board.

What are the vesting terms for Anne Prener’s 13,786 RSUs at KROS?

The 13,786 RSUs vest over three years in twelve equal quarterly installments. The first vesting date is August 15, 2026, and each installment requires Anne Prener’s continuous service through the applicable vesting date to receive the underlying Keros Therapeutics shares.

What are the key terms of Anne Prener’s 14,870-share stock option at Keros Therapeutics?

Anne Prener’s stock option covers 14,870 shares of Keros Therapeutics common stock at a $10.88 exercise price. It vests in equal quarterly installments over three years starting October 1, 2026, and expires June 30, 2036, subject to her continuous service through each vesting date.

Did Anne Prener buy or sell Keros Therapeutics (KROS) shares in this Form 4?

No open-market buying or selling occurred in this Form 4. The transactions reflect compensation-related acquisitions: grants of 13,786 RSUs and a 14,870-share stock option, both awarded at a stated price of $0.00 per share on the grant date.

How many Keros Therapeutics shares does Anne Prener hold after the RSU grant?

Following the RSU grant, the Form 4 reports 13,786 shares of Keros Therapeutics common stock associated with the restricted stock unit award. These shares will be delivered over time as the RSUs vest under the three-year quarterly vesting schedule described in the filing.

When do Anne Prener’s new Keros Therapeutics equity awards start vesting?

The RSU award begins vesting on August 15, 2026, in twelve equal quarterly installments over three years. The stock option begins vesting on October 1, 2026, also in equal quarterly installments over three years, subject to Anne Prener’s continuous service.

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

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Accepted by SEC EDGAR 07/06/2026 - 04:31 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^*

Prener Anne

(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)
07/01/2026

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	07/01/2026		A		13,786(1)	A	$0	13,786	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)	$10.88	07/01/2026		A		14,870		(2)	06/30/2036	Common Stock	14,870	$0	14,870	D

Explanation of Responses:

1. Represents a restricted stock unit ("RSU") award. The RSUs shall vest over a three-year period in twelve equal quarterly installments with the first such vesting to occur on August 15, 2026, subject to the Reporting Person's continuous service through each such vesting date.

2. The shares subject to the option shall vest over a three-year period in equal quarterly installments with the first such vesting to occur on October 1, 2026, subject to the Reporting Person's continuous service through each such vesting date.

	/s/ Esther Cho, Attorney-in-Fact	07/06/2026
	** 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)