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ZBIO SCHEDULE 13G: SEC filing

Wellington Management Group LLP and affiliated entities

Filed with the SEC on · accession 0000902219-26-000315

ZBIO filed a SCHEDULE 13G (schedule 13g) with the SEC on Sep 8, 2026. Wellington Management Group LLP and affiliated entities filed a joint filing agreement in connection with a Schedule 13G disclosing their beneficial ownership of Zenas BioPharma, Inc. common stock. The stock moved +0.5% by the first close after the filing.

Summary of the filing

Wellington Management Group LLP and affiliated entities filed a joint filing agreement in connection with a Schedule 13G disclosing their beneficial ownership of Zenas BioPharma, Inc. common stock. The filing is a routine passive institutional ownership disclosure.

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Key details

Reporting holder / filerWellington Management Group LLP
Reporting holder / filerWellington Group Holdings LLP
Reporting holder / filerWellington Investment Advisors Holdings LLP
Reporting holder / filerWellington Management Company LLP
Issuer of common stockZenas BioPharma, Inc.
Compliance manager, wellington management group llpMatthew Revell

How ZBIO stock reacted

Close before

$32.88

Sep 4, 2026

First close after

+0.52%

$33.05

5 trading days

-2.95%

$31.91

Since filing

-14.05%

$28.26

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Frequently asked questions

What did ZBIO file with the SEC on Sep 8, 2026?

ZBIO filed a SCHEDULE 13G (SEC filing). Wellington Management Group LLP and affiliated entities filed a joint filing agreement in connection with a Schedule 13G disclosing their beneficial ownership of Zenas BioPharma, Inc. common stock. The filing is a routine passive institutional ownership disclosure.

How do I read a SCHEDULE 13G?

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 13G (schedule 13g): A report the company filed with the SEC (the US market regulator).

How did ZBIO stock react to this filing?

ZBIO closed at $32.88 before the filing and $33.05 on Sep 8, 2026 (+0.52%). Five trading days later: $31.91 (-2.95%).

Other ZBIO SEC filings

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