Boundless Bio (BOLD): ADAR1 Capital discloses 8.8% beneficial ownership stake

Rhea-AI Filing Summary

Boundless Bio, Inc. has disclosed that private investment funds managed by ADAR1 Capital Management, LLC beneficially own 1,968,216 shares of its common stock. This represents 8.8% of Boundless Bio’s common stock, based on 22,475,000 shares outstanding as of June 30, 2026.

The shares are reported as being subject to shared voting and dispositive power by ADAR1 Capital Management and Daniel Schneeberger, who is the sole manager of ADAR1 Capital Management and may be deemed to indirectly beneficially own the same 1,968,216 shares.

Key Figures

Shares beneficially owned: 1,968,216 shares Percent of class: 8.8% Shares outstanding: 22,475,000 shares +2 more

5 metrics

Shares beneficially owned 1,968,216 shares Common stock of Boundless Bio beneficially owned by funds managed by ADAR1 Capital Management

Percent of class 8.8% Portion of Boundless Bio common stock beneficially owned by the reporting persons

Shares outstanding 22,475,000 shares Boundless Bio common stock outstanding as of June 30, 2026, from its Form 10-Q

Shared voting power 1,968,216 shares Shares over which the reporting persons have shared power to vote or direct the vote

Shared dispositive power 1,968,216 shares Shares over which the reporting persons have shared power to dispose or direct disposition

Key Terms

beneficially owned, shared voting power, shared dispositive power, Schedule 13G, +2 more

6 terms

beneficially owned financial

"The amounts reported in boxes 6, 8, and 9 represent 1,968,216 shares of common stock... beneficially owned"

Beneficially owned describes securities or assets where a person has the economic rights and control—such as the right to receive dividends and to direct voting—even if legal title is held in another name. Think of it like having the keys and using a car that’s registered to someone else: you get the benefits and make decisions. Investors care because beneficial ownership reveals who truly controls value and voting power, affecting corporate decisions and takeover dynamics.

shared voting power financial

"Shared Voting Power 1,968,216.00"

Shared voting power occurs when two or more parties jointly have the right to vote or decide how a block of company shares is cast, like co-owners who must agree before moving a piece of furniture. Investors care because who controls voting rights affects board elections, major corporate decisions and takeover outcomes, and shared control can alter regulatory disclosures and the practical influence any holder has over a company’s direction and value.

shared dispositive power financial

"Shared Dispositive Power 1,968,216.00"

Schedule 13G regulatory

"This Schedule is being filed on behalf of each of the following persons"

A Schedule 13G is a formal document that investors file with the government when they acquire a large ownership stake in a company, usually for investment purposes rather than control. It helps keep the public informed about who owns significant parts of a company's shares, which can influence how the company is managed and how investors make decisions. Filing this schedule is important for transparency and understanding the ownership landscape of publicly traded companies.

control person regulatory

"Mr. Schneeberger is filing this as a control person in respect of shares"

A control person is an individual or entity that can significantly influence a company’s decisions and direction through ownership, voting power, or contractual rights—think of them as the captain who can steer the ship. Investors care because a control person’s choices affect corporate strategy, board appointments, and transactions that can raise or lower a stock’s value, and they often carry additional legal responsibilities and disclosure requirements to protect other shareholders.

investment adviser financial

"ADAR1 Capital Management, an investment adviser as described in SS 240.13d-1(b)(1)(ii)(E)"

An investment adviser is a person or firm that professionally manages money and gives recommendations about buying, selling, or holding investments. Like a financial coach or guide, they have a legal duty to act in a client's best financial interest, so their advice, fees and potential conflicts can directly affect returns and risk — making their role important for investors who want informed, accountable help with portfolios.

FAQ

How much of Boundless Bio, Inc. (BOLD) does ADAR1 Capital Management beneficially own?

ADAR1 Capital Management’s managed funds beneficially own 1,968,216 shares of Boundless Bio common stock, representing 8.8% of the company’s outstanding shares, based on 22,475,000 shares outstanding as of June 30, 2026.

Who are the reporting persons in this Schedule 13G for Boundless Bio (BOLD)?

The reporting persons are ADAR1 Capital Management, LLC, a Texas limited liability company, and Daniel Schneeberger, a citizen of Switzerland and sole manager of ADAR1 Capital Management, who may be deemed to indirectly beneficially own the same shares.

What voting and dispositive powers are reported over Boundless Bio (BOLD) shares?

The reporting persons disclose 0 shares with sole voting or dispositive power and 1,968,216 shares with shared voting and shared dispositive power, reflecting the shares held by private investment funds managed by ADAR1 Capital Management.

What is the share count baseline used for the 8.8% stake in Boundless Bio (BOLD)?

The 8.8% beneficial ownership is calculated using 22,475,000 shares of Boundless Bio common stock outstanding as of June 30, 2026, as reported in the company’s Form 10-Q for that quarter.

In what capacity is Daniel Schneeberger reporting ownership in Boundless Bio (BOLD)?

Daniel Schneeberger reports as a control person with respect to shares beneficially owned by ADAR1 Capital Management, an investment adviser. He signs both as manager of ADAR1 Capital Management and in his individual capacity, reflecting potential indirect beneficial ownership.

Where are the principal offices of Boundless Bio (BOLD) and the reporting persons located?

Boundless Bio’s principal executive offices are at 11099 North Torrey Pines Road, Suite 150, La Jolla, CA 92037. The reporting persons’ principal business office is at 3503 Wild Cherry Drive, Building 9, Austin, Texas 78738.

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

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Available on EDGAR 08/14/2026 - 09:29 PM Accepted by SEC EDGAR 08/14/2026 - 09:28 PM Learn about SEC filing dates

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

Boundless Bio, Inc.

(Name of Issuer)

Common Stock, par value $0.0001 per share

(Title of Class of Securities)

10170A100

(CUSIP Number)

06/30/2026

(Date of Event Which Requires Filing of this Statement)

Check the appropriate box to designate the rule pursuant to which this Schedule is filed:

Rule 13d-1(b)

Rule 13d-1(c)

Rule 13d-1(d)

schemaVersion:

SCHEDULE 13G

CUSIP Number(s): 10170A100

1

Names of Reporting Persons

ADAR1 Capital Management, LLC

2

Check the appropriate box if a member of a Group (see instructions)

(a)
(b)

3

Sec Use Only

4

Citizenship or Place of Organization

TEXAS

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 1,968,216.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 1,968,216.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

1,968,216.00

10

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

11

Percent of class represented by amount in row (9)

8.8 %

12

Type of Reporting Person (See Instructions)

IA, OO

Comment for Type of Reporting Person: The amounts reported in boxes 6, 8, and 9 represent 1,968,216 shares of common stock, par value $0.0001 per share ("Common Stock"), of Boundless Bio, Inc. (the "Issuer") owned directly by private investment funds managed by ADAR1 Capital Management, LLC. Such securities may be deemed to be indirectly beneficially owned by ADAR1 Capital Management, LLC. The percentage in box 11 is based on 22,475,000 shares of Common Stock outstanding as of June 30, 2026, as reported in the Issuer's Quarterly Report on Form 10-Q for the quarter ended June 30, 2026, filed with the Securities and Exchange Commission on August 7, 2026.

SCHEDULE 13G

CUSIP Number(s): 10170A100

1

Names of Reporting Persons

Daniel Schneeberger

2

Check the appropriate box if a member of a Group (see instructions)

(a)
(b)

3

Sec Use Only

4

Citizenship or Place of Organization

SWITZERLAND

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 1,968,216.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 1,968,216.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

1,968,216.00

10

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

11

Percent of class represented by amount in row (9)

8.8 %

12

Type of Reporting Person (See Instructions)

HC, IN

Comment for Type of Reporting Person: The amounts reported in boxes 6, 8, and 9 represent 1,968,216 shares of common stock, par value $0.0001 per share ("Common Stock"), of Boundless Bio, Inc. (the "Company") owned directly by private investment funds managed by ADAR1 Capital Management, LLC. Such securities may be deemed to be indirectly beneficially owned by Daniel Schneeberger, the sole manager of ADAR1 Capital Management, LLC. The percentage in box 11 is based on 22,475,000 shares of Common Stock outstanding as of June 30, 2026, as reported in the Issuer's Quarterly Report on Form 10-Q for the quarter ended June 30, 2026, filed with the Securities and Exchange Commission on August 7, 2026.

SCHEDULE 13G

Item 1.
(a)	Name of issuer: Boundless Bio, Inc.
(b)	Address of issuer's principal executive offices: 11099 North Torrey Pines Road, Suite 150, La Jolla, CA 92037
Item 2.
(a)	Name of person filing: This Schedule is being filed on behalf of each of the following persons (each, a "Reporting Person" and collectively, the "Reporting Persons"): (i) ADAR1 Capital Management, LLC ("ADAR1 Capital Management"); and (ii) Daniel Schneeberger ("Mr. Schneeberger").
(b)	Address or principal business office or, if none, residence: The address of the principal business office of each of the Reporting Persons is 3503 Wild Cherry Drive, Building 9, Austin, Texas 78738.
(c)	Citizenship: (i) ADAR1 Capital Management is a Texas limited liability company; and (ii) Mr. Schneeberger is a citizen of Switzerland.
(d)	Title of class of securities: Common Stock, par value $0.0001 per share
(e)	CUSIP Number(s): 10170A100
Item 3.	If this statement is filed pursuant to §§ 240.13d-1(b) or 240.13d-2(b) or (c), check whether the person filing is a:
(a)	Broker or dealer registered under section 15 of the Act (15 U.S.C. 78o);
(b)	Bank as defined in section 3(a)(6) of the Act (15 U.S.C. 78c);
(c)	Insurance company as defined in section 3(a)(19) of the Act (15 U.S.C. 78c);
(d)	Investment company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8);
(e)	An investment adviser in accordance with § 240.13d-1(b)(1)(ii)(E);
(f)	An employee benefit plan or endowment fund in accordance with § 240.13d-1(b)(1)(ii)(F);
(g)	A parent holding company or control person in accordance with § 240.13d-1(b)(1)(ii)(G);
(h)	A savings associations as defined in Section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813);
(i)	A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the Investment Company Act of 1940 (15 U.S.C. 80a-3);
(j)	A non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J). If filing as a non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J), please specify the type of institution:
(k)	Group, in accordance with Rule 240.13d-1(b)(1)(ii)(K).
Item 4.	Ownership
(a)	Amount beneficially owned: The information contained on the cover pages of this Schedule 13G is incorporated herein by reference.
(b)	Percent of class: The information contained on the cover pages of this Schedule 13G is incorporated herein by reference.
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: The information contained on the cover pages of this Schedule 13G is incorporated herein by reference.
	(ii) Shared power to vote or to direct the vote: The information contained on the cover pages of this Schedule 13G is incorporated herein by reference.
	(iii) Sole power to dispose or to direct the disposition of: The information contained on the cover pages of this Schedule 13G is incorporated herein by reference.
	(iv) Shared power to dispose or to direct the disposition of: The information contained on the cover pages of this Schedule 13G is incorporated herein by reference.
Item 5.	Ownership of 5 Percent or Less of a Class.
	Not Applicable
Item 6.	Ownership of more than 5 Percent on Behalf of Another Person.
	Not Applicable
Item 7.	Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on by the Parent Holding Company or Control Person.
	If a parent holding company has filed this schedule, pursuant to Rule 13d-1(b)(ii)(G), so indicate under Item 3(g) and attach an exhibit stating the identity and the Item 3 classification of the relevant subsidiary. If a parent holding company has filed this schedule pursuant to Rule 13d-1(c) or Rule 13d-1(d), attach an exhibit stating the identification of the relevant subsidiary. Mr. Schneeberger is filing this Schedule 13G as a control person in respect of shares beneficially owned by ADAR1 Capital Management, an investment adviser as described in SS 240.13d-1(b)(1)(ii)(E).
Item 8.	Identification and Classification of Members of the Group.
	Not Applicable
Item 9.	Notice of Dissolution of Group.
	Not Applicable

Item 10.

Certifications:

By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were acquired and are held in the ordinary course of business and were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect, other than activities solely in connection with a nomination under § 240.14a-11.

SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

ADAR1 Capital Management, LLC

Signature:	/s/ Daniel Schneeberger
Name/Title:	Daniel Schneeberger, Manager
Date:	08/14/2026

Daniel Schneeberger

Signature:	/s/ Daniel Schneeberger
Name/Title:	Daniel Schneeberger, in his individual capacity
Date:	08/14/2026

Exhibit Information

Exhibit A: Joint Filing Agreement