Jessica Oien - 23 Jan 2026 Form 4 Insider Report for Boundless Bio, Inc. (BOLD)

Role: Chief Legal Officer and Corporate Secretary
Signature: /s/ Jessica Oien
Issuer symbol: BOLD
Transactions as of: 23 Jan 2026
Net transactions value: $0
Form type: 4
Filing time: 26 Jan 2026, 07:00:09 UTC
Previous filing: 23 Jan 2025
SEC: View on sec.gov

Reporting Owners (1)

Name	Relationship	Address	Signature	Signature date	CIK
Oien Jessica	Chief Legal Officer and Corporate Secretary	C/O BOUNDLESS BIO, INC., 10955 ALEXANDRIA WAY, SUITE 100, SAN DIEGO	/s/ Jessica Oien	23 Jan 2026	0001760712

Derivative Securities (e.g., puts, calls, warrants, options, convertible securities)

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Underlying Class	Amount	Exercise Price	Ownership	Footnotes
transaction	BOLD	Stock Option (right to buy)	Award	$0	+220,000		$0.000000	220,000	23 Jan 2026	Common Stock	220,000	$1.26	Direct	F1

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

Explanation of Responses:

Id	Content
F1	The vesting commencement date is January 1, 2026. The stock option vests in 48 substantially equal monthly installments. Accordingly, 1/48th of this stock option vests on February 1, 2026, and monthly thereafter.

Remarks:

Chief Legal Officer and Corporate Secretary