Paradigm reports MBX holdings on Schedule 13G

MBX Biosciences reports institutional holdings disclosed on a Schedule 13G showing Paradigm-related reporting persons beneficially owning disclosed stakes as of June 16, 2026.

Rhea-AI Filing Summary

MBX Biosciences reports institutional holdings disclosed on a Schedule 13G showing Paradigm-related reporting persons beneficially owning disclosed stakes as of June 16, 2026.

The filing lists Paradigm BioCapital Advisors, Paradigm BioCapital Advisors GP LLC, Senai Asefaw, M.D., and Paradigm BioCapital International Fund Ltd. with reported sole voting and dispositive power over specified share counts. The ownership percentages use an outstanding share base of 47,597,536 shares as of May 4, 2026.

Insights

Corporate Governance Analyst

Institutional stake disclosed; voting and dispositive power specified for Paradigm entities.

The filing documents that the Adviser, its GP, the managing member, and the Fund each report beneficial ownership positions with sole voting and sole dispositive power for the listed share amounts. The schedule ties percentages to May 4, 2026 outstanding shares.

Key dependencies include the issuer's reported 47,597,536 shares outstanding and the reporting persons' disclaimers. Subsequent filings may update holdings.

Institutional Ownership Specialist

Rounded institutional positions provide context on ownership concentration.

The excerpt shows Paradigm-related entities holding multiple million-share positions (e.g., 2,493,015 and 2,187,207 shares). Each reporting person disclaims ownership beyond the shares they directly beneficially own.

Disclosure clarifies voting/dispositive powers per cover-page lines and the joint-filing relationship; cash-flow treatment and trading intent are not stated in the excerpt.

Key Figures

Outstanding shares: 47,597,536 shares Paradigm BioCapital Advisors ownership: 2,493,015 shares Paradigm BioCapital International Fund ownership: 2,187,207 shares +1 more

4 metrics

Outstanding shares 47,597,536 shares as of May 4, 2026 (used to calculate percentages)

Paradigm BioCapital Advisors ownership 2,493,015 shares reported sole voting and dispositive power; Date of Event June 16, 2026

Paradigm BioCapital International Fund ownership 2,187,207 shares reported sole voting and dispositive power; Date of Event June 16, 2026

Reported ownership percentage (example) 5.2% Paradigm BioCapital Advisors percentage based on May 4, 2026 outstanding shares

Key Terms

Schedule 13G, Beneficially own / beneficial ownership, Sole voting power / Sole dispositive power

3 terms

Schedule 13G regulatory

"Item 1. Name of issuer: MBX Biosciences, Inc."

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.

Beneficially own / beneficial ownership regulatory

"The Fund and one or more separately managed accounts managed by the Adviser directly beneficially own the Common Stock"

Sole voting power / Sole dispositive power regulatory

"Sole Voting Power 2,493,015.00 ... Sole Dispositive Power 2,493,015.00"

FAQ

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

What stake does Paradigm report in MBX (MBX)?

Paradigm-related reporting persons report ownership including 2,493,015 shares and 2,187,207 shares. These figures appear on the cover‑page ownership lines and are dated June 16, 2026.

How was the percent ownership calculated in the Schedule 13G?

Percentages are calculated using 47,597,536 shares outstanding as of May 4, 2026, cited from the issuer's prior Form 10-Q filed May 7, 2026, and used in Item 4(b) of this filing.

Which reporting persons filed the Schedule 13G for MBX?

The filing is by Paradigm BioCapital Advisors LP, Paradigm BioCapital Advisors GP LLC, Senai Asefaw, M.D., and Paradigm BioCapital International Fund Ltd., as named in Item 2(a) of the statement.

Do the reporting persons claim sole voting or dispositive power?

Yes; the cover‑page lines show sole voting power and sole dispositive power equal to the listed share amounts for the reporting persons (e.g., 2,493,015 shares).

What date reflects the ownership information on this filing?

The filing states the amounts are given as of the close of business on June 16, 2026, which is identified as the Date of Event requiring this statement.

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

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Accepted by SEC EDGAR 06/24/2026 - 04:05 PM Learn about SEC filing dates

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

MBX Biosciences, Inc.

(Name of Issuer)

Common Stock, $0.0001 par value per share

(Title of Class of Securities)

55287L101

(CUSIP Number)

06/16/2026

(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): 55287L101

1

Names of Reporting Persons

Paradigm BioCapital Advisors LP

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

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 2,493,015.00
6	Shared Voting Power 0.00
7	Sole Dispositive Power 2,493,015.00
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

2,493,015.00

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)

5.2 %

12

Type of Reporting Person (See Instructions)

PN

SCHEDULE 13G

CUSIP Number(s): 55287L101

1

Names of Reporting Persons

Paradigm BioCapital Advisors GP 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

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 2,493,015.00
6	Shared Voting Power 0.00
7	Sole Dispositive Power 2,493,015.00
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

2,493,015.00

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)

5.2 %

12

Type of Reporting Person (See Instructions)

OO

Comment for Type of Reporting Person: limited liability company

SCHEDULE 13G

CUSIP Number(s): 55287L101

1

Names of Reporting Persons

Senai Asefaw, M.D.

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

UNITED STATES

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 2,493,015.00
6	Shared Voting Power 0.00
7	Sole Dispositive Power 2,493,015.00
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

2,493,015.00

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)

5.2 %

12

Type of Reporting Person (See Instructions)

IN

SCHEDULE 13G

CUSIP Number(s): 55287L101

1

Names of Reporting Persons

Paradigm BioCapital International Fund Ltd.

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

CAYMAN ISLANDS

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 2,187,207.00
6	Shared Voting Power 0.00
7	Sole Dispositive Power 2,187,207.00
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

2,187,207.00

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)

4.6 %

12

Type of Reporting Person (See Instructions)

CO

SCHEDULE 13G

Item 1.
(a)	Name of issuer: MBX Biosciences, Inc.
(b)	Address of issuer's principal executive offices: 11711 N. Meridian Street Suite 300 Carmel IN 46032
Item 2.
(a)	Name of person filing: This Schedule 13G is filed by the following (the "Reporting Persons"): (1) Paradigm BioCapital Advisors LP (the "Adviser"); (2) Paradigm BioCapital Advisors GP LLC (the "Adviser GP"); (3) Senai Asefaw, M.D. ("Senai Asefaw"); and (4) Paradigm BioCapital International Fund Ltd. (the "Fund"). The Fund is a private investment vehicle. The Fund and one or more separately managed accounts managed by the Adviser (the "Account") directly beneficially own the Common Stock reported in this statement. The Adviser is the investment manager of the Fund and the Account. The Adviser GP is the general partner of the Adviser. Senai Asefaw is the managing member of the Adviser GP. The Adviser, the Adviser GP and Senai Asefaw may be deemed to beneficially own the Common Stock directly beneficially owned by the Fund and the Account. Each Reporting Person disclaims beneficial ownership with respect to any Common Stock other than the Common Stock directly beneficially owned by such Reporting Person.
(b)	Address or principal business office or, if none, residence: The principal business office of the Fund is c/o Walkers, 190 Elgin Avenue, George Town, Grand Cayman KY1-9001, Cayman Islands. The principal business office of the Adviser, the Adviser GP and Senai Asefaw is 520 Fifth Avenue, 23rd Floor, New York, NY 10036.
(c)	Citizenship: For citizenship or place of organization see Item 4 of the cover page of each Reporting Person.
(d)	Title of class of securities: Common Stock, $0.0001 par value per share
(e)	CUSIP Number(s): 55287L101
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: See Item 9 on the cover page for each Reporting Person, and Item 2, which information is given as of the close of business on June 16, 2026, the Date of Event which requires the filing of this Schedule 13G.
(b)	Percent of class: See Item 11 on the cover page for each Reporting Person. The percentages of beneficial ownership contained herein are based on 47,597,536 shares of Common Stock outstanding as of May 4, 2026, as reported by the Issuer in its Form 10-Q filed with the SEC on May 7, 2026.
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: See Item 5 on the cover page for each Reporting Person.
	(ii) Shared power to vote or to direct the vote: See Item 6 on the cover page for each Reporting Person.
	(iii) Sole power to dispose or to direct the disposition of: See Item 7 on the cover page for each Reporting Person.
	(iv) Shared power to dispose or to direct the disposition of: See Item 8 on the cover page for each Reporting Person.
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.
	Not Applicable
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 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.

Paradigm BioCapital Advisors LP

Signature:	/s/ David K. Kim
Name/Title:	David K. Kim / Authorized Signatory
Date:	06/24/2026

Paradigm BioCapital Advisors GP LLC

Signature:	/s/ David K. Kim
Name/Title:	David K. Kim / Authorized Signatory
Date:	06/24/2026

Senai Asefaw, M.D.

Signature:	/s/ Senai Asefaw, M.D.
Name/Title:	N/A
Date:	06/24/2026

Paradigm BioCapital International Fund Ltd.

Signature:	/s/ David K. Kim
Name/Title:	David K. Kim / Authorized Signatory
Date:	06/24/2026

Exhibit Information

Exhibit 99.1 - Joint Filing Agreement