Boundless Bio (BOLD) awards 140,000-share stock option to finance chief

Rhea-AI Filing Summary

Boundless Bio, Inc. reported that officer David A. Hinkle received a new stock option award. On January 23, 2026, he was granted an option to purchase 140,000 shares of common stock at an exercise price of $1.26 per share.

The option’s vesting start date is January 1, 2026. It vests in 48 substantially equal monthly installments, so 1/48 of the option vests on February 1, 2026 and then continues to vest monthly until fully vested on the fourth anniversary, assuming continued service.

SEC Form 4

FORM 4

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
or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL

OMB Number:			3235-0287
Estimated average burden
hours per response:			0.5

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

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

HINKLE DAVID A

(Last) (First) (Middle)

C/O BOUNDLESS BIO, INC.

10955 ALEXANDRIA WAY, SUITE 100

(Street)

SAN DIEGO CA 92121

(City) (State) (Zip)

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

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

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

3. Date of Earliest Transaction (Month/Day/Year)
01/23/2026

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

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	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)
			Code	V	Amount	(A) or (D)	Price

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: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Stock Option (right to buy)	$1.26	01/23/2026		A		140,000		(1)	01/22/2036	Common Stock	140,000	$0	140,000	D

Explanation of Responses:

1. 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:

Senior VP, Finance, Controller and Treasurer

	/s/ Jessica Oien, Attorney-in- Fact for David A. Hinkle	01/23/2026
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.

FAQ

What insider transaction did Boundless Bio (BOLD) report for David A. Hinkle?

Boundless Bio reported that officer David A. Hinkle received a grant of a stock option covering 140,000 shares of common stock on January 23, 2026.

What is the exercise price of David A. Hinkle’s new stock option at Boundless Bio (BOLD)?

The stock option granted to David A. Hinkle has an exercise price of $1.26 per share for Boundless Bio common stock.

How many Boundless Bio (BOLD) shares are covered by David A. Hinkle’s option grant?

The reported stock option covers 140,000 shares of Boundless Bio common stock, all held under a single option award.

When does David A. Hinkle’s Boundless Bio (BOLD) stock option begin vesting?

The vesting commencement date is January 1, 2026, with the first tranche (1/48) vesting on February 1, 2026.

What is the vesting schedule for David A. Hinkle’s Boundless Bio (BOLD) option grant?

The option vests in 48 substantially equal monthly installments. 1/48 vests on February 1, 2026, and the remainder vests monthly thereafter until fully vested.

What role does David A. Hinkle hold at Boundless Bio (BOLD)?

The filing identifies David A. Hinkle as an officer of Boundless Bio, with remarks stating he is Senior VP, Finance, Controller and Treasurer.

Is David A. Hinkle’s Boundless Bio (BOLD) option held directly or indirectly?

The Form 4 indicates the 140,000 derivative securities are held with direct (D) ownership by David A. Hinkle.