ADAR1 Capital Management, LLC - 15 Oct 2025 Form 4 Insider Report for Keros Therapeutics, Inc. (KROS)

Role: 10%+ Owner
Signature: ADAR1 Capital Management, LLC By: Daniel Schneeberger, Manager /s/ Daniel Schneeberger
Issuer symbol: KROS
Transactions as of: 15 Oct 2025
Net transactions value: -$95,659,436
Form type: 4
Filing time: 15 Oct 2025, 13:24:20 UTC
Previous filing: 24 Jun 2025
SEC: View on sec.gov

Reporting Owners (4)

Name	Relationship	Address	Signature	Signature date	CIK
ADAR1 Capital Management, LLC	10%+ Owner	3503 WILD CHERRY DRIVE, BUILDING 9, AUSTIN	ADAR1 Capital Management, LLC By: Daniel Schneeberger, Manager /s/ Daniel Schneeberger	15 Oct 2025	0001940272
ADAR1 Partners, LP	10%+ Owner	3503 WILD CHERRY DRIVE, BUILDING 9, AUSTIN	ADAR1 Partners, LP By: Daniel Schneeberger, Manager /s/ Daniel Schneeberger	15 Oct 2025	0001758866
ADAR1 Capital Management GP, LLC	10%+ Owner	3503 WILD CHERRY DRIVE, BUILDING 9, AUSTIN	ADAR1 Capital Management GP, LLC By: Daniel Schneeberger, Manager /s/ Daniel Schneeberger	15 Oct 2025	0001940267
Schneeberger Daniel	10%+ Owner	3503 WILD CHERRY DRIVE, BUILDING 9, AUSTIN	Daniel Schneeberger, Manager /s/ Daniel Schneeberger	15 Oct 2025	0001861120

Transactions Table

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Date	Ownership	Footnotes
transaction	KROS	Common Stock	Sale	$77,944,457	-4,391,237	-100%	$17.75	15 Oct 2025	By ADAR1 Partners, LP	F1, F2
transaction	KROS	Common Stock	Sale	$4,520,375	-254,669	-100%	$17.75	15 Oct 2025	By ADAR1 SPVI, LP	F1, F2
transaction	KROS	Common Stock	Sale	$13,194,604	-743,358	-100%	$17.75	15 Oct 2025	By Spearhead Insurance Solutions IDF, LLC	F1, F2

* An asterisk sign (*) next to the price indicates that the price is likely invalid.

ADAR1 Capital Management, LLC is no longer subject to Section 16 filing requirements. Form 4 or Form 5 obligations may continue.

Explanation of Responses:

Id	Content
F1	The securities to which this filing relates are held directly by ADAR1 Partners, LP, ADAR1 SPV I, LP and Spearhead Insurance Solutions IDF, LLC. As the investment manager of ADAR1 Partners, LP and ADAR1 SPV I, LP and as the sub-advisor of Spearhead Insurance Solutions IDF, LLC, ADAR1 Capital Management, LLC may be deemed to indirectly beneficially own securities held by ADAR1 Partners, LP, ADAR1 SPV I, LP and Spearhead Insurance Solutions IDF, LLC. As the general partner of ADAR1 Partners, LP and ADAR1 SPV I, LP, ADAR1 Capital Management GP, LLC may be deemed to indirectly beneficially own securities held by ADAR1 Partners, LP and ADAR1 SPV I, LP. As the manager of ADAR1 Capital Management, LLC and ADAR1 Capital Management GP, LLC, Daniel Schneeberger may be deemed to indirectly beneficially own securities held by ADAR1 Partners, LP, Spearhead Insurance Solutions IDF, LLC, and ADAR1 SPV I, LP.
F2	For purposes of Section 16 of the Securities Exchange Act of 1934, as amended, each Reporting Person disclaims beneficial ownership of any such securities, except to the extent of his/its pecuniary interest therein, if any, and this report shall not be deemed an admission that such Reporting Person is the beneficial owner of such securities for purposes of Section 16 or otherwise.

Content

The securities to which this filing relates are held directly by ADAR1 Partners, LP, ADAR1 SPV I, LP and Spearhead Insurance Solutions IDF, LLC. As the investment manager of ADAR1 Partners, LP and ADAR1 SPV I, LP and as the sub-advisor of Spearhead Insurance Solutions IDF, LLC, ADAR1 Capital Management, LLC may be deemed to indirectly beneficially own securities held by ADAR1 Partners, LP, ADAR1 SPV I, LP and Spearhead Insurance Solutions IDF, LLC. As the general partner of ADAR1 Partners, LP and ADAR1 SPV I, LP, ADAR1 Capital Management GP, LLC may be deemed to indirectly beneficially own securities held by ADAR1 Partners, LP and ADAR1 SPV I, LP. As the manager of ADAR1 Capital Management, LLC and ADAR1 Capital Management GP, LLC, Daniel Schneeberger may be deemed to indirectly beneficially own securities held by ADAR1 Partners, LP, Spearhead Insurance Solutions IDF, LLC, and ADAR1 SPV I, LP.

For purposes of Section 16 of the Securities Exchange Act of 1934, as amended, each Reporting Person disclaims beneficial ownership of any such securities, except to the extent of his/its pecuniary interest therein, if any, and this report shall not be deemed an admission that such Reporting Person is the beneficial owner of such securities for purposes of Section 16 or otherwise.