Janus Henderson (JHG) Form 3 Initial statement of insider ownership

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

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1. Name and Address of Reporting Person^*

JANUS HENDERSON GROUP PLC

(Last) (First) (Middle)

201 BISHOPGATE

(Street)

LONDON X0 EC2M 3AE

(City) (State) (Zip)

2. Date of Event Requiring Statement (Month/Day/Year)
07/02/2024

3. Issuer Name and Ticker or Trading Symbol
ARCA biopharma, Inc. [ ABIO ]

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

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

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

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)
Common Stock	1,482,535	I	By Fund(1)

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

1. Name and Address of Reporting Person^*

JANUS HENDERSON GROUP PLC

(Last) (First) (Middle)

201 BISHOPGATE

(Street)

LONDON X0 EC2M 3AE

(City) (State) (Zip)

1. Name and Address of Reporting Person^*

Janus Henderson Biotech Innovation Master Fund Ltd

(Last) (First) (Middle)

201 BISHOPGATE

(Street)

LONDON X0 EC2M 3AE

(City) (State) (Zip)

Explanation of Responses:

1. The securities reported are beneficially owned directly by Janus Henderson Biotech Innovation Master Fund Ltd. (the "Fund"). Janus Henderson Group plc has a 100% ownership stake in Janus Henderson Investors US LLC, which serves as the investment advisor to the Fund, and may therefore be deemed a beneficial owner of the securities reported herein. Each Reporting Person disclaims beneficial ownership of the securities reported herein except to the extent of its pecuniary interest therein, if any.

	/s/ Michelle Rosenberg, CAO, General Counsel & Company Secretary	07/12/2024
	/s/ Janus Henderson Biotech Innovation Master Fund Ltd., By: Janus Henderson Investors US LLC, By: Peter Falconer, Assistant Secretary	07/12/2024
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
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