Large owner Crandell Keith exercised 16,000 shares at a strike of $1.03 and sold $39,840 worth of shares (16,000 units at $2.49) (SEC Form 4)
$BOLD
Biotechnology: Pharmaceutical Preparations
Health Care
| 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 |
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| 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*
(Street)
(Country) | 2. Issuer Name and Ticker or Trading Symbol
Boundless Bio, Inc. [ BOLD ] | 5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
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| 2a. Foreign Trading Symbol
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| 3. Date of Earliest Transaction
(Month/Day/Year) 07/01/2026 | 6. Individual or Joint/Group Filing (Check Applicable Line)
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| 4. If Amendment, Date of Original Filed
(Month/Day/Year) |
| Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned | ||||||||||
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| 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 | ||||||
| Common Stock | 07/01/2026 | M | 16,000 | A | $1.03 | 16,000 | I | See footnote(1) | ||
| Common Stock | 07/01/2026 | S | 16,000 | D | $2.49 | 0 | I | See footnote(1) | ||
| Common Stock | 683,759 | I | See footnotes(2)(4) | |||||||
| Common Stock | 828,570 | I | See footnotes(3)(4) | |||||||
| Common Stock | 1,181,766 | I | See footnotes(5)(6) | |||||||
| Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities) | |||||||||||||||
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| 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 | 07/01/2026 | M | 16,000 | (7) | 06/22/2035 | Common Stock | 16,000 | $0 | 0 | I | See footnote(1) | |||
1. Name and Address of Reporting Person*
(Street)
Relationship of Reporting Person(s) to Issuer
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1. Name and Address of Reporting Person*
(Street)
Relationship of Reporting Person(s) to Issuer
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1. Name and Address of Reporting Person*
(Street)
Relationship of Reporting Person(s) to Issuer
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1. Name and Address of Reporting Person*
(Street)
Relationship of Reporting Person(s) to Issuer
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1. Name and Address of Reporting Person*
(Street)
Relationship of Reporting Person(s) to Issuer
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| Explanation of Responses: |
| 1. Represents a cashless stock option exercise by Kristina Burow. The net proceeds of such exercise were remitted to ARCH Venture Fund IX, L.P. (ARCH IX), ARCH Venture Fund IX Overage, L.P. (ARCH IX Overage), and ARCH Venture Fund X, L.P. (AVF X Overage LP). The stock option was granted to Kristina Burow in connection with her service on the board of directors of the Issuer. |
| 2. Represents shares held directly by ARCH Venture Fund IX, L.P. (ARCH IX). ARCH Venture Partners IX, L.P. (AVP IX LP) is the sole general partner of ARCH IX. |
| 3. Represents shares held directly by ARCH Venture Fund IX Overage, L.P. (ARCH IX Overage). ARCH Venture Partners IX Overage, L.P. (AVP IX Overage LP) is the sole general partner of ARCH IX Overage. |
| 4. ARCH Venture Partners IX, LLC (AVP IX LLC) is the sole general partner of each of AVP IX LP and AVP IX Overage LP. Keith Crandell, Robert Nelsen and Clinton Bybee are managing directors of AVP IX LLC (the AVP IX MDs). AVP IX LP and AVP IX Overage LP may be deemed to beneficially own the shares held by ARCH IX and ARCH IX Overage, respectively, AVP IX LLC may be deemed to beneficially own the shares held by ARCH IX and ARCH IX Overage, and each of the AVP IX MDs may be deemed to share the power to direct the disposition and vote of the shares held by ARCH IX and ARCH IX Overage. AVP IX LP, AVP IX Overage LP, AVP IX LLC, and the AVP IX MDs each disclaim beneficial ownership except to to the extent of any pecuniary interest therein, if any. |
| 5. Represents shares held directly by ARCH Venture Fund X Overage, L.P. (ARCH X Overage). ARCH Venture Partners X Overage, L.P. (AVP X Overage LP) is the sole general partner of ARCH X Overage. |
| 6. ARCH Venture Partners X, LLC (AVP X LLC) is the sole general partner of AVP X Overage LP. Keith Crandell, Kristina Burow, Robert Nelsen and Steven Gillis are members of the investment committee of AVP X LLC (the AVP X Committee Members). AVP X Overage LP may be deemed to beneficially own the shares held by ARCH X Overage, AVP X LLC may be deemed to beneficially own the shares held by ARCH X Overage, and each of the AVP X Committee Members may be deemed to share the power to direct the disposition and vote of the shares held by ARCH X Overage. AVP X Overage LP, AVP X LLC, and the AVP X Committee Members each disclaim beneficial ownership except to the extent of any pecuniary interest therein, if any. |
| 7. The stock option vested in substantially equal monthly installments over the 11 months following June 23, 2025. The final unvested portion vested on June 15, 2026, the date of the Issuer's 2026 annual meeting of stockholders. |
| Remarks: |
| This Form 4 is one of two reports relating to the same transaction being filed jointly by ARCH IX, AVP IX LP, ARCH IX Overage, AVP IX Overage LP, AVP IX LLC, ARCH X Overage, AVP X Overage LP, AVP X LLC, Robert Nelsen, Keith Crandell, Kristina Burow, Steve Gillis and Clint Bybee. |
| /s/ Keith Crandell, By: Mark McDonnell, attorney in-fact | 07/06/2026 | |
| /s/ Clinton Bybee, By: Mark McDonnell, attorney in-fact | 07/06/2026 | |
| /s/ Robert Nelsen, By: Mark McDonnell, attorney in-fact | 07/06/2026 | |
| /s/ Steven Gillis, By: Mark McDonnell, attorney in-fact | 07/06/2026 | |
| /s/ Kristina Burow, By: Mark McDonnell, attorney in-fact | 07/06/2026 | |
| ** 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. | ||
| * Form 4: SEC 1474 (03-26) | ||