Fairmount Funds Management LLC - 31 Mar 2026 Form 4 Insider Report for Zenas BioPharma, Inc. (ZBIO)

Reporting relationship: Director
Issuer ticker: ZBIO
Reported as of: 31 Mar 2026
Net transaction value: +$3,000,000
SEC form: 4
Accepted by SEC: 01 Apr 2026, 16:30:31 UTC
Prior SEC filing: 25 Mar 2026
Next SEC filing: 13 May 2026
Source filing: View source filing
Reporting owner signature: /s/ Tomas Kiselak, Managing Member of Fairmount Funds Management LLC

Key filing fact

Fairmount Funds Management LLC filed Form 4 for Zenas BioPharma, Inc. (ZBIO) on 01 Apr 2026.

Key facts

This page summarizes Fairmount Funds Management LLC's Form 4 filing for Zenas BioPharma, Inc. (ZBIO).
1 reported transaction and 0 derivative rows are listed below.
Accepted by SEC: 01 Apr 2026, 16:30.

Change

Previous filing in this sequence was filed on 25 Mar 2026.
Current net transaction value: +$3,000,000.

Research use

This tells you what this filing adds before you inspect full transaction and derivative tables.
You can trace every row back to the original SEC filing document.

Evidence

Filed on Form 4

Ownership activity is grounded in SEC Form 4 disclosures.

View source filing

Reporting Owners (4)

CIK 0001802528 Primary reporting owner

Fairmount Funds Management LLC

Relationship: Director
Address: 200 BARR HARBOR DRIVE, SUITE 400, WEST CONSHOHOCKEN
Signature: /s/ Tomas Kiselak, Managing Member of Fairmount Funds Management LLC
Signature date: 01 Apr 2026

CIK 0001769651

Fairmount Healthcare Fund II L.P.

Relationship: Director
Address: 200 BARR HARBOR DRIVE, SUITE 400, WEST CONSHOHOCKEN
Signature: /s/ Tomas Kiselak, Managing Member of Fairmount Healthcare Fund II, L.P.
Signature date: 01 Apr 2026

CIK 0001830177

Kiselak Tomas

Relationship: Director
Address: 200 BARR HARBOR DRIVE, SUITE 400, WEST CONSHOHOCKEN
Signature: /s/ Tomas Kiselak
Signature date: 01 Apr 2026

CIK 0001663607

Harwin Peter Evan

Relationship: Director
Address: 200 BARR HARBOR DRIVE, SUITE 400, WEST CONSHOHOCKEN
Signature: /s/ Peter Harwin
Signature date: 01 Apr 2026

Reported non-derivative transactions

Shares, units, or other non-derivative securities reported in this filing.

ZBIO transaction

Common Stock

Purchase

Transaction value: $3,000,000
Shares: +150,000
Change %: +6.8%
Price: $20.00
Shares after: 2,359,025
Date: 31 Mar 2026
Ownership: By Fairmount Healthcare Fund II L.P.
Footnotes: F1

ZBIO transaction

Common Stock

Purchase

Transaction value: $3,000,000
Shares: +150,000
Change %: +6.8%
Price: $20.00
Shares after: 2,359,025
Date: 31 Mar 2026
Ownership: By Fairmount Healthcare Fund II L.P.
Footnotes: F1

ZBIO transaction

Common Stock

Purchase

Transaction value: $3,000,000
Shares: +150,000
Change %: +6.8%
Price: $20.00
Shares after: 2,359,025
Date: 31 Mar 2026
Ownership: By Fairmount Healthcare Fund II L.P.
Footnotes: F1

ZBIO transaction

Common Stock

Purchase

Transaction value: $3,000,000
Shares: +150,000
Change %: +6.8%
Price: $20.00
Shares after: 2,359,025
Date: 31 Mar 2026
Ownership: By Fairmount Healthcare Fund II L.P.
Footnotes: F1

^* marks a reported price that did not pass the local price check.

Additional SEC filing notes

Filing notes and footnotes

Explanation of responses 1 footnote

Footnote F1

Fairmount Funds Management LLC ("Fairmount") is the investment manager for Fairmount Healthcare Fund II L.P. The managers of Fairmount are Peter Harwin and Tomas Kiselak. Fairmount, Mr. Harwin, and Mr. Kiselak disclaim beneficial ownership of any of the reported securities, except to the extent of their pecuniary interest therein.

SEC remarks

Fairmount may be deemed a director by deputization of Issuer by virtue of the fact that Tomas Kiselak serves on the board of directors of the Issuer and is also a Managing Member of Fairmount.