[Form 3] Hemab Therapeutics Holdings, Inc. Initial Statement of Beneficial Ownership

Rhea-AI Filing Summary

Hemab Therapeutics Holdings, Inc. insiders associated with RA Capital filed an initial ownership report showing indirect holdings of Series A, B and C Preferred Stock. These preferred shares are each convertible into Common Stock on a 22-for-1 basis immediately prior to the closing of the company’s initial public offering for no additional consideration.

The filing lists indirect positions held by RA Capital Healthcare Fund LP and RA Capital Nexus Funds II and IV, including Series A Preferred Stock convertible into 609,840 and 1,422,960 underlying Common Stock shares, Series B Preferred Stock convertible into 399,212 and 931,502 underlying shares, and Series C Preferred Stock convertible into 221,188 and 1,253,384 underlying shares. RA Capital Management and related parties disclaim beneficial ownership except to the extent of their pecuniary interest.

Insider Trade Summary

6 transactions reported

Mixed 6 txns

Insider RA CAPITAL MANAGEMENT, L.P., RA Capital Healthcare Fund LP, RA Capital Nexus Fund II, L.P., RA Capital Nexus Fund IV, L.P., Kolchinsky Peter, Shah Rajeev M.

Role Director, 10% Owner | Director | Director | Director | Director, 10% Owner | Director, 10% Owner

Type	Security	Shares	Price	Value
holding	Series A Preferred Stock	--	--	--
holding	Series A Preferred Stock	--	--	--
holding	Series B Preferred Stock	--	--	--
holding	Series B Preferred Stock	--	--	--
holding	Series C Preferred Stock	--	--	--
holding	Series C Preferred Stock	--	--	--

Holdings After Transaction: Series A Preferred Stock — 2,032,800 shares (Indirect, See footnotes); Series B Preferred Stock — 1,330,714 shares (Indirect, See footnotes); Series C Preferred Stock — 1,474,572 shares (Indirect, See footnotes)

Footnotes (5)

1. F1. Each share of Series A Preferred Stock, Series B Preferred Stock and Series C Preferred Stock will automatically convert into shares of Common Stock on a 22-for-1 basis immediately prior to the closing of the Issuer's initial public offering for no additional consideration and has no expiration date.
2. F2. RA Capital Management, L.P. (the "Adviser") is the investment manager for RA Capital Healthcare Fund, L.P. (the "Fund"), RA Capital Nexus II Fund, L.P. (the "Nexus Fund II") and RA Capital Nexus IV Fund, L.P. (the "Nexus Fund IV"). The general partner of the Adviser is RA Capital Management GP, LLC (the "Adviser GP"), of which Dr. Peter Kolchinsky and Mr. Rajeev Shah are the managing members. The Adviser, the Adviser GP, the Fund, the Nexus Fund II, the Nexus Fund IV, Dr. Kolchinsky and Mr. Shah disclaim beneficial ownership of any of the reported securities, except to the extent of their pecuniary interest therein.
3. F3. Held directly by the Fund.
4. F4. Held directly by Nexus Fund II.
5. F5. Held directly by Nexus Fund IV.

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Accepted by SEC EDGAR 04/30/2026 - 06:36 PM Learn about SEC filing dates

SEC Form 3

FORM 3

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

INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES

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:			3235-0104
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hours per response:			0.5

1. Name and Address of Reporting Person^*

RA CAPITAL MANAGEMENT, L.P.

(Last) (First) (Middle)

200 BERKELEY STREET, 18TH FLOOR

(Street)

BOSTON MASSACHUSETTS 02116

(City) (State) (Zip)

UNITED STATES

(Country)

2. Date of Event Requiring Statement (Month/Day/Year)
04/30/2026

3. Issuer Name and Ticker or Trading Symbol
Hemab Therapeutics Holdings, Inc. [ COAG ]

3a. Foreign Trading Symbol

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

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

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

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 Beneficially Owned
1. Title of Security (Instr. 4)	2. Amount of Securities Beneficially Owned (Instr. 4)	3. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	4. Nature of Indirect Beneficial Ownership (Instr. 5)

Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 4)	2. Date Exercisable and Expiration Date (Month/Day/Year)		3. Title and Amount of Securities Underlying Derivative Security (Instr. 4)		4. Conversion or Exercise Price of Derivative Security	5. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	6. Nature of Indirect Beneficial Ownership (Instr. 5)
	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Series A Preferred Stock	(1)	(1)	Common Stock	1,422,960	(1)	I	See footnotes(2)(3)
Series A Preferred Stock	(1)	(1)	Common Stock	609,840	(1)	I	See footnotes(2)(4)
Series B Preferred Stock	(1)	(1)	Common Stock	931,502	(1)	I	See footnotes(2)(3)
Series B Preferred Stock	(1)	(1)	Common Stock	399,212	(1)	I	See footnotes(2)(4)
Series C Preferred Stock	(1)	(1)	Common Stock	1,253,384	(1)	I	See footnotes(2)(3)
Series C Preferred Stock	(1)	(1)	Common Stock	221,188	(1)	I	See footnotes(2)(5)

1. Name and Address of Reporting Person^*

RA CAPITAL MANAGEMENT, L.P.

(Last) (First) (Middle)

200 BERKELEY STREET, 18TH FLOOR

(Street)

BOSTON MASSACHUSETTS 02116

(City) (State) (Zip)

UNITED STATES

(Country)

Relationship of Reporting Person(s) to Issuer

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

1. Name and Address of Reporting Person^*

RA Capital Healthcare Fund LP

(Last) (First) (Middle)

C/O RA CAPITAL MANAGEMENT, L.P.

200 BERKELEY STREET, 18TH FLOOR

(Street)

BOSTON MASSACHUSETTS 02116

(City) (State) (Zip)

UNITED STATES

(Country)

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^*

RA Capital Nexus Fund II, L.P.

(Last) (First) (Middle)

C/O RA CAPITAL MANAGEMENT, L.P.

200 BERKELEY STREET, 18TH FLOOR

(Street)

BOSTON MASSACHUSETTS 02116

(City) (State) (Zip)

UNITED STATES

(Country)

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^*

RA Capital Nexus Fund IV, L.P.

(Last) (First) (Middle)

C/O RA CAPITAL MANAGEMENT, L.P.

200 BERKELEY STREET, 18TH FLOOR

(Street)

BOSTON MASSACHUSETTS 02116

(City) (State) (Zip)

UNITED STATES

(Country)

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^*

Kolchinsky Peter

(Last) (First) (Middle)

C/O RA CAPITAL MANAGEMENT, L.P.

200 BERKELEY STREET, 18TH FLOOR

(Street)

BOSTON MASSACHUSETTS 02116

(City) (State) (Zip)

UNITED STATES

(Country)

Relationship of Reporting Person(s) to Issuer

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

1. Name and Address of Reporting Person^*

Shah Rajeev M.

(Last) (First) (Middle)

C/O RA CAPITAL MANAGEMENT, L.P.

200 BERKELEY STREET, 18TH FLOOR

(Street)

BOSTON MASSACHUSETTS 02116

(City) (State) (Zip)

UNITED STATES

(Country)

Relationship of Reporting Person(s) to Issuer

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

Explanation of Responses:

1. Each share of Series A Preferred Stock, Series B Preferred Stock and Series C Preferred Stock will automatically convert into shares of Common Stock on a 22-for-1 basis immediately prior to the closing of the Issuer's initial public offering for no additional consideration and has no expiration date.

2. RA Capital Management, L.P. (the "Adviser") is the investment manager for RA Capital Healthcare Fund, L.P. (the "Fund"), RA Capital Nexus II Fund, L.P. (the "Nexus Fund II") and RA Capital Nexus IV Fund, L.P. (the "Nexus Fund IV"). The general partner of the Adviser is RA Capital Management GP, LLC (the "Adviser GP"), of which Dr. Peter Kolchinsky and Mr. Rajeev Shah are the managing members. The Adviser, the Adviser GP, the Fund, the Nexus Fund II, the Nexus Fund IV, Dr. Kolchinsky and Mr. Shah disclaim beneficial ownership of any of the reported securities, except to the extent of their pecuniary interest therein.

3. Held directly by the Fund.

4. Held directly by Nexus Fund II.

5. Held directly by Nexus Fund IV.

Remarks:

Dr. Laura Tadvalkar, a Managing Director of the Adviser, serves on the Issuer's board of directors.

	/s/ Peter Kolchinsky, Manager of RA Capital Management, L.P.	04/30/2026
	/s/ Peter Kolchinsky, Manager of RA Capital Healthcare Fund GP, LLC, the General Partner of RA Capital Healthcare Fund, L.P.	04/30/2026
	/s/ Peter Kolchinsky, Manager of RA Capital Nexus Fund II GP, LLC, the General Partner of RA Capital Nexus Fund II, L.P.	04/30/2026
	/s/ Peter Kolchinsky, Manager of RA Capital Nexus Fund IV GP, LLC, the General Partner of RA Capital Nexus Fund IV, L.P.	04/30/2026
	/s/ Peter Kolchinsky, individually	04/30/2026
	/s/ Rajeev Shah, individually	04/30/2026
	** Signature of Reporting Person	Date
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* Form 3: SEC 1473 (03-26)