ATLQU SCHEDULE 13G/A: SEC filing

Magnetar Financial LLC and affiliated reporting persons

Filed with the SEC on Nov 13, 2026 · accession 0001104659-26-126735

ATLQU filed a SCHEDULE 13G/A (schedule 13g/a) with the SEC on Nov 13, 2026. Magnetar Financial LLC and affiliated reporting persons filed an amended Schedule 13G disclosing beneficial ownership of 900,000 Class A ordinary shares, or approximately 4.84%, of Atlantic Acquisition Corp I (formerly JAB Acquisition Corp I) as of September 30, 2026. The stock moved +0.0% by the first close after the filing.

Summary of the filing

Magnetar Financial LLC and affiliated reporting persons filed an amended Schedule 13G disclosing beneficial ownership of 900,000 Class A ordinary shares, or approximately 4.84%, of Atlantic Acquisition Corp I (formerly JAB Acquisition Corp I) as of September 30, 2026. The filing is a passive investment disclosure and does not indicate any intent to influence control of the issuer.

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Key details

Class A ordinary shares beneficially owned$900K

Percentage of class beneficially ownedPCT 5

Reporting person / investment adviser to the magnetar fundsMagnetar Financial LLC

Reporting person / sole member and parent holding company of magnetar financialMagnetar Capital Partners LP

Reporting person / general partner of magnetar capital partnersSupernova Management LLC

Issuer (formerly jab acquisition corp i)Atlantic Acquisition Corp I

Administrative manager of supernova management llcDavid J. Snyderman

Attorney-in-factHayley Stein

How ATLQU stock reacted

Close before

$10.20

Nov 12, 2026

First close after

+0.00%

$10.20

5 trading days

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Since filing

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Frequently asked questions

What did ATLQU file with the SEC on Nov 13, 2026?

ATLQU filed a SCHEDULE 13G/A (SEC filing). Magnetar Financial LLC and affiliated reporting persons filed an amended Schedule 13G disclosing beneficial ownership of 900,000 Class A ordinary shares, or approximately 4.84%, of Atlantic Acquisition Corp I (formerly JAB Acquisition Corp I) as of September 30, 2026. The filing is a passive investment disclosure and does not indicate any intent to influence control of the issuer.

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 ATLQU stock react to this filing?

ATLQU closed at $10.20 before the filing and $10.20 on Nov 13, 2026 (+0.00%).

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