[Form 4] Boundless Bio, Inc. Insider Trading Activity

Rhea-AI Filing Summary

Form 4 Overview: On 06/23/2025, Boundless Bio, Inc. (ticker BOLD) filed a Form 4 disclosing a grant of derivative securities to director and 10% owner Kristina Burow.

• Security granted: Stock option (right to buy)
• Quantity: 16,000 options
• Exercise price: $1.03 per share
• Vesting schedule: Monthly over 12 months beginning 06/23/2025; any unvested portion accelerates to the next annual shareholder meeting if earlier.
• Expiration: 06/22/2035
• Ownership form after transaction: Direct (16,000 derivative securities)

No non-derivative share transactions were reported. The filing represents routine director compensation rather than an open-market purchase, and it does not include financial performance metrics or earnings data.

Insights

Securities Analyst

TL;DR: Routine option grant; minimal market impact.

The 16,000-share option grant to a director/10% owner is standard board compensation. No purchase of common stock occurred, so cash outlay and immediate dilution are nil. The relatively low $1.03 strike could indicate a depressed valuation baseline, but without share-price context the market signal is limited. Overall, the filing neither alters ownership materially nor conveys directional insight on near-term fundamentals.

Corporate Governance Expert

TL;DR: Governance-aligned equity award, standard practice.

The monthly vesting over 12 months aligns director incentives with shareholder interests through continuous service. Acceleration to the next AGM is typical for small-cap biotech boards. No red flags in structure, size, or pricing were detected. Given Burow already holds ≥10% equity, incremental governance impact is negligible.

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^*

Burow Kristina

(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)

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

3. Date of Earliest Transaction (Month/Day/Year)
06/23/2025

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)	$1.03	06/23/2025		A		16,000		(1)	06/22/2035	Common Stock	16,000	$0	16,000	D

Explanation of Responses:

1. The stock option shall vest in substantially equal monthly installments over the 12 months following June 23, 2025 (or, in the event the next annual meeting of the issuer's stockholders occurs prior to June 23, 2026, any remaining unvested portion of the stock option will vest on the date of such annual meeting), subject to the reporting person's continuing service on the issuer's board of directors through such vesting date.

	/s/ Jessica Oien, Attorney-in-Fact for Kristina Burow	06/23/2025
	** 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 did Boundless Bio (BOLD) disclose in the latest Form 4?

A grant of 16,000 stock options to director and 10% owner Kristina Burow on 06/23/2025 at an exercise price of $1.03.

How many shares are underlying the new options for Kristina Burow?

The option grant covers 16,000 shares of common stock.

What is the vesting schedule of the BOLD director’s option grant?

The options vest monthly over 12 months after 06/23/2025, or fully at the next annual meeting if earlier.

When do the new options granted to Kristina Burow expire?

The options expire on 06/22/2035.

Did the Form 4 include any open-market stock purchases or sales?

No. Only an option grant was reported; no common stock transactions occurred.