Boundless Bio investor Kevin Tang buys 91,585 shares

Boundless Bio, Inc. ten percent owner entities associated with Kevin Tang reported open-market purchases of a total of 91,585 shares of Common Stock on July 9, 10 and 13, 2026, at weighted-average prices of $2.48, $2.43 and $2.42 per share, respectively.

Rhea-AI Filing Summary

Boundless Bio, Inc. ten percent owner entities associated with Kevin Tang reported open-market purchases of a total of 91,585 shares of Common Stock on July 9, 10 and 13, 2026, at weighted-average prices of $2.48, $2.43 and $2.42 per share, respectively. Following the latest transaction, investment vehicles managed by Tang Capital Management LLC, in which Kevin Tang has a pecuniary interest, beneficially own 2,790,103 shares of Boundless Bio common stock indirectly.

Filing Explained

The filing records indirect open-market purchases, with beneficial ownership reaching 2,790,103 shares; it does not establish a structural change for issuer or common holders.

Form 4 reports an insider transaction, and the July 13 filing records completed purchases of Boundless Bio common stock through July 13, with indirect beneficial ownership reported at 2,790,103 shares afterward.

The transactions are coded P, meaning open-market purchases, rather than sales, option exercises, grants, or tax withholdings. The filing reports purchases of 7 shares on July 9, 2026, 43,367 shares on July 10, 2026, and 48,211 shares on July 13, 2026.

The reported prices are weighted averages: $2.48 for the July 9 purchase, $2.43 for July 10, and $2.42 for July 13. The filing attributes the indirect holdings to Tang Capital entities and states that Kevin Tang has a pecuniary interest in those shares.

Insider Trade Summary

Net Buyer: 91,585 shares

Net Buy 3 txns

Insider TANG KEVIN, TANG CAPITAL MANAGEMENT LLC

Role 10% Owner | 10% Owner

Bought 91,585 shs ($222K)

Type	Security	Shares	Price	Value
Purchase	Common Stock F4, F2	48,211	$2.42	$117K
Purchase	Common Stock F3, F2	43,367	$2.43	$105K
Purchase	Common Stock F1, F2	7	$2.48	$17.36

Holdings After Transaction: Common Stock — 2,790,103 shares (Indirect, See Footnote)

Footnotes (4)

1. F1. The prices reported are weighted-average prices. These shares were all purchased at $2.48. 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 4.
2. F2. Tang Capital Partners, LP ("TCP") beneficially owns 639,395 shares, Tang Capital Partners International, LP ("TCPI") beneficially owns 871,923 shares, Tang Capital Partners III, Inc. ("TCP III") beneficially owns 639,390 shares, and Tang Capital Partners IV, Inc. ("TCP IV") beneficially owns 639,395 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. F3. These shares were purchased in multiple transactions at prices ranging from $2.38 to $2.48.
4. F4. These shares were purchased in multiple transactions at prices ranging from $2.35 to $2.44.

Key Figures

Shares purchased: 91,585 shares Purchase price 13 Jul 2026: $2.42 per share Purchase price 10 Jul 2026: $2.43 per share +5 more

8 metrics

Shares purchased 91,585 shares Total Boundless Bio common shares bought in open-market transactions from July 9–13, 2026

Purchase price 13 Jul 2026 $2.42 per share Weighted-average price for 48,211 shares of Common Stock purchased on July 13, 2026

Purchase price 10 Jul 2026 $2.43 per share Weighted-average price for 43,367 shares of Common Stock purchased on July 10, 2026

Purchase price 9 Jul 2026 $2.48 per share Weighted-average price for 7 shares of Common Stock purchased on July 9, 2026

Post-transaction holdings 2,790,103 shares Common shares of Boundless Bio beneficially owned indirectly by Tang-affiliated entities after July 13, 2026

Tang Capital Partners, LP holdings 639,395 shares Boundless Bio common shares beneficially owned by Tang Capital Partners, LP (TCP)

Tang Capital Partners International, LP holdings 871,923 shares Boundless Bio common shares beneficially owned by Tang Capital Partners International, LP (TCPI)

Tang Capital Partners III, Inc. holdings 639,390 shares Boundless Bio common shares beneficially owned by Tang Capital Partners III, Inc. (TCP III)

Key Terms

weighted-average prices, beneficially owns, pecuniary interest, indirectly wholly owned, +1 more

5 terms

weighted-average prices financial

"The prices reported are weighted-average prices."

beneficially owns financial

"Tang Capital Partners, LP ("TCP") beneficially owns 639,395 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"

indirectly wholly owned financial

"TCP III and TCP IV, which are indirectly wholly owned by TCP."

indirect ownership financial

"total_shares_following_transaction ... ownership_type "indirect""

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What did Kevin Tang report buying in Boundless Bio (BOLD) common stock?

Kevin Tang, through entities managed by Tang Capital Management LLC, reported open-market purchases totaling 91,585 shares of Boundless Bio Common Stock. The trades occurred on July 9, 10 and 13, 2026, and are reported as indirect ownership with a pecuniary interest.

On what dates did the Boundless Bio (BOLD) purchases by Tang-affiliated entities occur?

The reported Boundless Bio purchases occurred on July 9, 2026 (7 shares), July 10, 2026 (43,367 shares), and July 13, 2026 (48,211 shares). All transactions involved Common Stock acquired in open-market purchases reported on a Form 4 filing.

What prices were paid for the Boundless Bio (BOLD) shares in these Form 4 transactions?

The reported weighted-average purchase prices were $2.48 per share on July 9, $2.43 per share on July 10, and $2.42 per share on July 13, 2026. Footnotes note multiple trades within ranges from $2.35 to $2.48 per share.

How many Boundless Bio (BOLD) shares do Tang-affiliated entities hold after these purchases?

After the July 13, 2026 purchases, Tang-affiliated investment vehicles beneficially own 2,790,103 shares of Boundless Bio Common Stock indirectly. This figure reflects holdings reported as indirect ownership with Kevin Tang having a pecuniary interest through several related entities.

Which Tang Capital entities beneficially own Boundless Bio (BOLD) shares according to the Form 4 footnotes?

Footnotes state that Tang Capital Partners, LP holds 639,395 shares, Tang Capital Partners International, LP holds 871,923 shares, and Tang Capital Partners III, Inc. holds 639,390 shares of Boundless Bio. A related entity, Tang Capital Partners IV, Inc., also beneficially owns Boundless Bio shares.

Are the Boundless Bio (BOLD) shares held directly by Kevin Tang or through entities?

The reported Boundless Bio shares are held indirectly through entities including Tang Capital Partners, LP, Tang Capital Partners International, LP and related companies. Kevin Tang is manager or director of these entities and has a pecuniary interest in their Boundless Bio holdings.

AI-generated analysis. How Rhea-AI works. Not financial advice.

Form 4 Insider Transactions: What Each Field Means →

See more from StockTitan in Google Search and AI answers. Adds StockTitan as a preferred source · opens Google

Add on Google Not now

Accepted by SEC EDGAR 07/13/2026 - 07:06 PM Learn about SEC filing dates

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^*

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)

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

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
07/09/2026

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

	Form filed by One Reporting Person
X	Form 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)
			Code	V	Amount	(A) or (D)	Price
Common Stock	07/09/2026		P		7	A	$2.48(1)	2,698,525	I	See Footnote(2)
Common Stock	07/10/2026		P		43,367	A	$2.43(3)	2,741,892	I	See Footnote(2)
Common Stock	07/13/2026		P		48,211	A	$2.42(4)	2,790,103	I	See Footnote(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)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount 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

	Director	X	10% 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

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

Explanation of Responses:

1. The prices reported are weighted-average prices. These shares were all purchased at $2.48. 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 4.

2. Tang Capital Partners, LP ("TCP") beneficially owns 639,395 shares, Tang Capital Partners International, LP ("TCPI") beneficially owns 871,923 shares, Tang Capital Partners III, Inc. ("TCP III") beneficially owns 639,390 shares, and Tang Capital Partners IV, Inc. ("TCP IV") beneficially owns 639,395 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 purchased in multiple transactions at prices ranging from $2.38 to $2.48.

4. These shares were purchased in multiple transactions at prices ranging from $2.35 to $2.44.

	Kevin Tang	07/13/2026
	Kevin Tang, Manager	07/13/2026
	** 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)