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ZBIO SCHEDULE 13D/A: SEC filing

SR One Capital Management and affiliated entities

Filed with the SEC on · accession 0001072613-26-000694

ZBIO filed a SCHEDULE 13D/A (schedule 13d/a) with the SEC on Aug 17, 2026. SR One Capital Management and affiliated entities filed a joint Schedule 13D/A regarding their ownership of Zenas BioPharma, Inc. common stock. The stock moved +3.4% by the first close after the filing.

Summary of the filing

SR One Capital Management and affiliated entities filed a joint Schedule 13D/A regarding their ownership of Zenas BioPharma, Inc. common stock. The filing consists of a joint filing agreement executed by the reporting persons.

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Key details

Issuer/subject companyZenas BioPharma, Inc.
Reporting person / filerSR One Capital Management, LLC
Reporting personSR One Capital Fund II Aggregator, LP
Reporting personSR One Capital Partners II, LP
Reporting personAMZL, LP
Reporting personSR One Capital SMA Partners, LP
Reporting personSR One Capital Opportunities Fund I, LP
Reporting personSR One Capital Opportunities Partners I, LP
Managing member, sr one capital management, llcSimeon George, M.D.
Attorney-in-factSasha Keough

How ZBIO stock reacted

Close before

$29.51

Aug 14, 2026

First close after

+3.35%

$30.50

5 trading days

+9.42%

$32.29

Since filing

-4.24%

$28.26

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Frequently asked questions

What did ZBIO file with the SEC on Aug 17, 2026?

ZBIO filed a SCHEDULE 13D/A (SEC filing). SR One Capital Management and affiliated entities filed a joint Schedule 13D/A regarding their ownership of Zenas BioPharma, Inc. common stock. The filing consists of a joint filing agreement executed by the reporting persons.

How do I read a SCHEDULE 13D/A?

A report the company filed with the SEC (the US market regulator). Start with the summary, then the key amounts and names. Compare it with the company’s earlier filings.

Why are SEC filings important?

Public companies must tell the SEC about anything that can change their value — results, leadership changes, big deals, new shares, bankruptcy. Filings are the official source, often before the news. A SCHEDULE 13D/A (schedule 13d/a): A report the company filed with the SEC (the US market regulator).

How did ZBIO stock react to this filing?

ZBIO closed at $29.51 before the filing and $30.50 on Aug 17, 2026 (+3.35%). Five trading days later: $32.29 (+9.42%).

Other ZBIO SEC filings

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