RA Capital Healthcare Fund LP Form 4 Filed 2024-04-04

FORM 4

☒	Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

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, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person ^*

RA CAPITAL MANAGEMENT, L.P.

2. Issuer Name and Ticker or Trading Symbol
Boundless Bio, Inc. [BOLD]

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

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

(Last)

(First)

(Middle)

200 BERKELEY STREET,

3. Date of Earliest Transaction (Month/Day/Year)
04/02/2024

(Street)

BOSTON, MA 02116

(City)

(State)

(Zip)

4. If Amendment, Date 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 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)
1.Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	Code	V	Amount	(A) or (D)	Price		6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
Common Stock	04/02/2024		C		1,587,912	A	⁽¹⁾	1,587,912	I	See footnotes⁽²⁾⁽³⁾
Common Stock	04/02/2024		P		296,875	A	$16	1,884,787	I	See footnotes⁽²⁾⁽³⁾
Common Stock	04/02/2024		C		280,219	A	⁽¹⁾	280,219	I	See footnotes⁽³⁾⁽⁴⁾
Common Stock	04/02/2024		P		15,625	A	$16	295,844	I	See footnotes⁽³⁾⁽⁴⁾

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 of Derivative Security: Direct (D) or Indirect (I) (Instr. 4)

11. Nature of Indirect Beneficial Ownership (Instr. 4)

Code

(A)

(D)

Date Exercisable

Expiration Date

Title

Amount or Number of Shares

Series B Preferred Stock

⁽¹⁾

04/02/2024

17,000,000

⁽¹⁾

Common Stock

871,794

$ 0

See footnotes⁽²⁾⁽³⁾

Series B Preferred Stock

⁽¹⁾

04/02/2024

3,000,000

⁽¹⁾

Common Stock

153,846

$ 0

See footnotes⁽³⁾⁽⁴⁾

Series C Preferred Stock

⁽¹⁾

04/02/2024

13,964,285

⁽¹⁾

Common Stock

716,118

$ 0

See footnotes⁽²⁾⁽³⁾

Series C Preferred Stock

⁽¹⁾

04/02/2024

2,464,286

⁽¹⁾

Common Stock

126,373

$ 0

See footnotes⁽³⁾⁽⁴⁾

Reporting Owners

Reporting Owner Name / Address	Relationships
Reporting Owner Name / Address	Director	10% Owner	Officer	Other
RA CAPITAL MANAGEMENT, L.P. 200 BERKELEY STREET BOSTON, MA 02116		X
RA Capital Healthcare Fund LP 200 BERKELEY STREET BOSTON, MA 02116		X
RA Capital Nexus Fund II, L.P. 200 BERKELEY STREET BOSTON, MA 02116		X
Kolchinsky Peter C/O RA CAPITAL MANAGEMENT, L.P. 200 BERKELEY STREET BOSTON, MA 02116		X
Shah Rajeev M. RA CAPITAL MANAGEMENT, L.P. 200 BERKELEY STREET, 18TH FLOOR BOSTON, MA 02116		X

Explanation of Responses:

1.	On April 2, 2024, each share of Series B Preferred Stock and Series C Preferred Stock automatically converted into shares of Common Stock on a 19.5-for-1 basis immediately prior to the closing of the Issuer's initial public offering. The shares of Series B Preferred Stock and Series C Preferred Stock had no expiration date.
2.	Held directly by RA Capital Healthcare Fund, L.P. (the "Fund").
3.	RA Capital Management, L.P. (the "Adviser") is the investment manager for the Fund and RA Capital Nexus Fund II, L.P. (the "Nexus Fund II"). 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, Dr. Kolchinsky, and Mr. Shah disclaim beneficial ownership of any of the reported securities, except to the extent of their pecuniary interest therein.
4.	Held directly by the Nexus Fund II.

	Signatures
	/s/ Peter Kolchinsky, Manager of RA Capital Management, L.P.	04/04/2024
	/s/ Peter Kolchinsky, Manager of RA Capital Healthcare Fund GP, LLC the General Partner of RA Capital Healthcare Fund, L.P.	04/04/2024
	/s/ Peter Kolchinsky, Manager of RA Capital Nexus Fund II GP, LLC the General Partner of RA Capital Nexus Fund II, L.P.	04/04/2024
	/s/ Peter Kolchinsky, individually	04/04/2024
	/s/ Rajeev Shah, individually	04/04/2024
	** Signature of Reporting Person	Date
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