STOCK TITAN

Boundless Bio (BOLD) major holder buys 107,463 Common shares

Filing Impact
(Moderate)
Filing Sentiment
(Positive)
Form Type
4

Rhea-AI Filing Summary

Boundless Bio, Inc. insider entities affiliated with Kevin Tang reported open-market purchases of a total of 107,463 shares of Common Stock at prices around $2.49–$2.60 per share over three days. The transactions were made indirectly through limited partnerships managed by Tang Capital Management, LLC.

Following these purchases, the reporting entities collectively beneficially own 2,641,308 shares of Boundless Bio Common Stock, as described in the filing’s ownership breakdown for Tang Capital Partners, LP and related entities. All reported trades were classified as open-market purchases, with no sales or derivative transactions disclosed.

Positive

  • None.

Negative

  • None.
Insider TANG KEVIN, TANG CAPITAL MANAGEMENT LLC
Role null | null
Bought 107,463 shs ($269K)
Type Security Shares Price Value
Purchase Common Stock 9,821 $2.49 $24K
Purchase Common Stock 71,612 $2.49 $178K
Purchase Common Stock 25,930 $2.54 $66K
Purchase Common Stock 100 $2.50 $250.00
Holdings After Transaction: Common Stock — 2,641,308 shares (Indirect, By LP)
Footnotes (1)
  1. The prices reported are weighted-average prices. These shares were purchased in multiple transactions at prices ranging from $2.49 to $2.60. The Reporting Persons undertake to provide the Issuer, any security holder of the Issuer or the SEC staff, upon request, all information regarding the number of shares purchased at each price within the ranges set forth in Footnotes 1 and 3 through 5. Tang Capital Partners, LP ("TCP") beneficially owns 605,296 shares, Tang Capital Partners International, LP ("TCPI") beneficially owns 825,422 shares, Tang Capital Partners III, Inc. ("TCP III") beneficially owns 605,294 shares, and Tang Capital Partners IV, Inc. ("TCP IV") beneficially owns 605,296 shares. Kevin Tang is the sole manager of Tang Capital Management, LLC, which is the general partner of TCP and TCPI. Kevin Tang is the sole director and Chief Executive Officer of TCP III and TCP IV, which are indirectly wholly owned by TCP. Mr. Tang has a pecuniary interest in the shares beneficially held by TCP, TCPI, TCP III and TCP IV. These shares were all purchased at $2.50. These shares were purchased in multiple transactions at prices ranging from $2.46 to $2.50. These shares were purchased in multiple transactions at prices ranging from $2.47 to $2.50.
Total shares purchased 107,463 shares Net open-market purchases reported in this Form 4
Price range $2.49–$2.60 per share Reported ranges for Boundless Bio Common Stock purchases
Post-transaction holdings 2,641,308 shares Beneficial ownership across Tang Capital-related entities after trades
July 2 purchase size 9,821 shares Open-market purchase on July 2, 2026 at $2.49 per share
July 1 purchase size 71,612 shares Open-market purchase on July 1, 2026 at $2.49 per share
June 30 larger purchase 25,930 shares Open-market purchase on June 30, 2026 at $2.54 per share
open-market purchase financial
"All reported trades were classified as open-market purchases, with no sales or derivative transactions disclosed."
An open-market purchase is when an investor or a company buys shares on a public stock exchange at the going market price, rather than through a private deal. It matters to investors because these purchases change how many shares are available, can push the stock price up or signal confidence from large buyers, and often affect per-share metrics like earnings—think of it like someone buying lots of apples off a grocery shelf, reducing supply and potentially raising the price.
beneficially owns financial
"Tang Capital Partners, LP ("TCP") beneficially owns 605,296 shares, Tang Capital Partners International, LP ("TCPI") beneficially owns 825,422 shares..."
Beneficially owns means a person or entity enjoys the economic benefits and control of a security even if the legal title or registration is held in another name. Think of it like having the keys and profits from a car that is registered to a friend: you use it, benefit from it, and make decisions about it even though the official paperwork lists someone else. For investors, this matters because it reveals who truly controls shares, affects voting power, potential conflicts of interest, and regulatory disclosure obligations.
pecuniary interest financial
"Mr. Tang has a pecuniary interest in the shares beneficially held by TCP, TCPI, TCP III and TCP IV."
limited partnerships financial
"These purchases occurred indirectly through limited partnerships managed by Tang Capital Management, LLC."
A limited partnership is a business structure with two types of partners: one or more general partners who run the business and carry full legal responsibility for its debts, and one or more limited partners who contribute money but do not take part in daily management and whose legal responsibility is capped at the amount they invested. For investors, this setup matters because it separates control from financial risk—like founders steering a boat while passive backers fund the trip—and determines who makes decisions, how profits and losses flow to owners for taxes, and how easily an investor can sell their stake.
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SEC Form 4
FORM 4UNITED 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*
TANG KEVIN

(Last)(First)(Middle)
4747 EXECUTIVE DRIVE
SUITE 210

(Street)
SAN DIEGO CALIFORNIA 92121

(City)(State)(Zip)

UNITED STATES

(Country)
2. Issuer Name and Ticker or Trading Symbol
Boundless Bio, Inc. [ BOLD ]
5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
DirectorX10% Owner
Officer (give title below)Other (specify below)
2a. Foreign Trading Symbol
3. Date of Earliest Transaction (Month/Day/Year)
06/30/2026
6. Individual or Joint/Group Filing (Check Applicable Line)
Form filed by One Reporting Person
XForm filed by More than One Reporting Person
4. If Amendment, Date of Original Filed (Month/Day/Year)

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)
CodeVAmount(A) or (D)Price
Common Stock06/30/2026P25,930A$2.54(1)2,559,775IBy LP(2)
Common Stock06/30/2026P100A$2.5(3)2,559,875IBy LP(2)
Common Stock07/01/2026P71,612A$2.49(4)2,631,487IBy LP(2)
Common Stock07/02/2026P9,821A$2.49(5)2,641,308IBy LP(2)
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)
CodeV(A)(D)Date ExercisableExpiration DateTitleAmount or Number of Shares
1. Name and Address of Reporting Person*
TANG KEVIN

(Last)(First)(Middle)
4747 EXECUTIVE DRIVE
SUITE 210

(Street)
SAN DIEGO CALIFORNIA 92121

(City)(State)(Zip)

UNITED STATES

(Country)

Relationship of Reporting Person(s) to Issuer
DirectorX10% Owner
Officer (give title below)Other (specify below)
1. Name and Address of Reporting Person*
TANG CAPITAL MANAGEMENT LLC

(Last)(First)(Middle)
4747 EXECUTIVE DRIVE
SUITE 210

(Street)
SAN DIEGO CALIFORNIA 92121

(City)(State)(Zip)

UNITED STATES

(Country)

Relationship of Reporting Person(s) to Issuer
DirectorX10% Owner
Officer (give title below)Other (specify below)
Explanation of Responses:
1. The prices reported are weighted-average prices. These shares were purchased in multiple transactions at prices ranging from $2.49 to $2.60. The Reporting Persons undertake to provide the Issuer, any security holder of the Issuer or the SEC staff, upon request, all information regarding the number of shares purchased at each price within the ranges set forth in Footnotes 1 and 3 through 5.
2. Tang Capital Partners, LP ("TCP") beneficially owns 605,296 shares, Tang Capital Partners International, LP ("TCPI") beneficially owns 825,422 shares, Tang Capital Partners III, Inc. ("TCP III") beneficially owns 605,294 shares, and Tang Capital Partners IV, Inc. ("TCP IV") beneficially owns 605,296 shares. Kevin Tang is the sole manager of Tang Capital Management, LLC, which is the general partner of TCP and TCPI. Kevin Tang is the sole director and Chief Executive Officer of TCP III and TCP IV, which are indirectly wholly owned by TCP. Mr. Tang has a pecuniary interest in the shares beneficially held by TCP, TCPI, TCP III and TCP IV.
3. These shares were all purchased at $2.50.
4. These shares were purchased in multiple transactions at prices ranging from $2.46 to $2.50.
5. These shares were purchased in multiple transactions at prices ranging from $2.47 to $2.50.
Kevin Tang07/02/2026
Kevin Tang, Manager07/02/2026
** Signature of Reporting PersonDate
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)

FAQ

How many Boundless Bio (BOLD) shares did the Tang-affiliated entities buy?

Tang-affiliated investment entities bought a total of 107,463 shares of Boundless Bio Common Stock. These purchases occurred over several days and were reported as open-market transactions at prices near $2.49–$2.60 per share, with no corresponding sales disclosed.

Over what dates did the Boundless Bio (BOLD) insider share purchases occur?

The reported insider purchases took place on June 30, July 1, and July 2, 2026. Each date reflects separate open-market transactions in Boundless Bio Common Stock by Tang-affiliated limited partnerships, with all trades reported as buys and no derivatives exercised.

What prices were paid for the Boundless Bio (BOLD) shares in these insider purchases?

Reported transaction prices were around $2.49–$2.60 per share of Boundless Bio Common Stock. Individual trades used weighted-average prices, and footnotes state that underlying executions occurred within specified price ranges on the reported transaction dates.

Were any Boundless Bio (BOLD) shares sold or derivatives exercised in this Form 4?

No sales or derivative exercises were reported. The Form 4 only discloses open-market purchases of Common Stock, with four separate buy transactions and zero reported sales, gifts, tax withholdings, or option exercises during the period covered.