MRCY SCHEDULE 13D/A: Activist campaign
JANA Partners
Filed with the SEC on · accession 0000902664-26-004458
MRCY filed a SCHEDULE 13D/A (schedule 13d/a) with the SEC on Nov 10, 2026. JANA Partners filed an amendment to its Schedule 13D reporting beneficial ownership of approximately 6.4% of Mercury Systems (3,880,671 shares) and filed for early termination of an existing Hart-Scott-Rodino antitrust clearance. The stock moved +5.0% by the first close after the filing.
Summary of the filing
JANA Partners filed an amendment to its Schedule 13D reporting beneficial ownership of approximately 6.4% of Mercury Systems (3,880,671 shares) and filed for early termination of an existing Hart-Scott-Rodino antitrust clearance. JANA stated the HSR filing is unrelated to any disagreement with the company.
Key details
How MRCY stock reacted
Close before
$79.62
Nov 9, 2026
First close after
+4.97%
$83.58
5 trading days
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Since filing
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Click hereFrequently asked questions
What did MRCY file with the SEC on Nov 10, 2026?
MRCY filed a SCHEDULE 13D/A (Activist campaign). JANA Partners filed an amendment to its Schedule 13D reporting beneficial ownership of approximately 6.4% of Mercury Systems (3,880,671 shares) and filed for early termination of an existing Hart-Scott-Rodino antitrust clearance. JANA stated the HSR filing is unrelated to any disagreement with the company.
What does a activist campaign mean for MRCY stock?
A settlement removes uncertainty; the stock often reacts to whether the amount is bigger or smaller than investors expected.
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 MRCY stock react to this filing?
MRCY closed at $79.62 before the filing and $83.58 on Nov 10, 2026 (+4.97%).
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