Julius Knowles - 03 Jun 2026 Form 4 Insider Report for Keros Therapeutics, Inc. (KROS)

Reporting relationship: Director
Issuer ticker: KROS
Reported as of: 03 Jun 2026
Net transaction value: $0
SEC form: 4
Accepted by SEC: 05 Jun 2026, 16:15:12 UTC
Prior SEC filing: 18 Dec 2025
Next SEC filing: 08 Jun 2026
Source filing: View source filing
Reporting owner signature: /s/ Keith Regnante, Attorney-in-Fact

Filing notes and source

Key filing fact

Julius Knowles filed Form 4 for Keros Therapeutics, Inc. (KROS) on 05 Jun 2026.

Key facts

This page summarizes Julius Knowles's Form 4 filing for Keros Therapeutics, Inc. (KROS).
2 reported transactions and 1 derivative row are listed below.
Accepted by SEC: 05 Jun 2026, 16:15.

Change

Previous filing in this sequence was filed on 18 Dec 2025.
Current net transaction value: $0.

Research use

This tells you what this filing adds before you inspect full transaction and derivative tables.
You can trace every row back to the original SEC filing document.

Evidence

Filed on Form 4

Ownership activity is grounded in SEC Form 4 disclosures.

View source filing

Reporting Owners (1)

CIK 0001808365 Primary reporting owner

Knowles Julius

Relationship: Director
Address: C/O KEROS THERAPEUTICS, INC., 1050 WALTHAM STREET, SUITE 302, LEXINGTON
Signature: /s/ Keith Regnante, Attorney-in-Fact
Signature date: 05 Jun 2026

Reported non-derivative transactions

Shares, units, or other non-derivative securities reported in this filing.

KROS transaction

Common Stock

Award

Transaction value
Shares: +7,142
Change %: +111%
Price: $0.000000^*
Shares after: 13,583
Date: 03 Jun 2026
Ownership: Direct
Footnotes: F1

KROS holding

Common Stock

No transaction description listed

Transaction value
Shares
Change %
Price
Shares after: 150,047
Date: 03 Jun 2026
Ownership: See footnote
Footnotes: F2

KROS holding

Common Stock

No transaction description listed

Transaction value
Shares
Change %
Price
Shares after: 102,233
Date: 03 Jun 2026
Ownership: See footnote
Footnotes: F3

Reported derivative securities

Options, warrants, convertible securities, or similar derivative positions disclosed in the filing.

KROS transaction Derivative

Stock Option (right to buy)

Award

Transaction value
Shares: +7,433
Change %
Price: $0.000000^*
Shares after: 7,433
Date: 03 Jun 2026
Ownership: Direct
Underlying class: Common Stock
Underlying amount: 7,433
Exercise price: $10.50
Footnotes: F4

^* marks a reported price that did not pass the local price check.

Additional SEC filing notes

Filing notes and footnotes

Explanation of responses 4 footnotes

Footnote 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.

Footnote F2

The securities are held by Partners Innovation Fund, LLC ("PIF I"). Partners Innovation Fund, LLC ("Partners GP I") is the ultimate general partner of PIF I. The Reporting Person, a member of the board of directors of the Issuer, is a partner of Partners GP I and as a result, may be deemed to share voting and investment power with respect to the shares held by PIF I.

Footnote F3

The securities are held by Partners Innovation Fund II, L.P. ("PIF II"). Partners Innovation Fund II, LLC ("Partners GP II") is the ultimate general partner of PIF II. The Reporting Person, a member of the board of directors of the Issuer, is a partner of Partners GP II and as a result, may be deemed to share voting and investment power with respect to the shares held by PIF II.

Footnote F4

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.