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MGNI SCHEDULE 13G/A: SEC filing

Wellington Management Group LLP and affiliated entities

Filed with the SEC on · accession 0000902219-26-000303

MGNI filed a SCHEDULE 13G/A (schedule 13g/a) with the SEC on Aug 13, 2026. Wellington Management Group LLP and affiliated entities filed a joint filing agreement as part of a Schedule 13G/A regarding their position in Magnite, Inc. common stock. The stock moved +1.0% by the first close after the filing.

Summary of the filing

Wellington Management Group LLP and affiliated entities filed a joint filing agreement as part of a Schedule 13G/A regarding their position in Magnite, Inc. common stock. The filing is an administrative attachment and does not disclose any change in ownership or intent.

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Key details

Filer / institutional holderWellington Management Group LLP
Filer / affiliated entityWellington Group Holdings LLP
Filer / affiliated entityWellington Investment Advisors Holdings LLP
Subject companyMagnite, Inc.
Compliance manager, wellington management group llpMatthew Revell

How MGNI stock reacted

Close before

$24.34

Aug 12, 2026

First close after

+0.99%

$24.58

5 trading days

-2.01%

$23.85

Since filing

+12.53%

$27.39

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Frequently asked questions

What did MGNI file with the SEC on Aug 13, 2026?

MGNI filed a SCHEDULE 13G/A (SEC filing). Wellington Management Group LLP and affiliated entities filed a joint filing agreement as part of a Schedule 13G/A regarding their position in Magnite, Inc. common stock. The filing is an administrative attachment and does not disclose any change in ownership or intent.

How do I read a SCHEDULE 13G/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 13G/A (schedule 13g/a): A report the company filed with the SEC (the US market regulator).

How did MGNI stock react to this filing?

MGNI closed at $24.34 before the filing and $24.58 on Aug 13, 2026 (+0.99%). Five trading days later: $23.85 (-2.01%).

Other MGNI SEC filings

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