Why do 13D filings move stocks?

A 13D means a sophisticated investor put serious capital behind a thesis that the company is mispriced or mismanaged — and now has to say so publicly. Target stocks often reprice on the disclosure itself, which is why the filing date, the event date (when they crossed 5%), and who was already positioned beforehand all matter.

Which activists file the most 13Ds?

In GovGreed's 2025–2026 window, the most frequent activist filers include Saba Capital Management (217 filings, mostly closed-end fund campaigns), RA Capital Management (58, biotech), GAMCO (58), Starboard Value (24), John C. Malone (23) and Tether Holdings (26). Filing counts include amendments.

Did members of Congress buy before activists filed?

In roughly 180 cases since January 2025, at least one member of Congress disclosed a purchase of a ticker in the 90 days BEFORE an activist 13D landed on it. GovGreed lists each case with the members and purchase counts. Correlation is not coordination — the overlap is published so readers can inspect the timing themselves.

How is this data collected?

Weekly, from SEC EDGAR full-text search, parsing the structured XML inside each filing — issuer CIK, lead reporting person, aggregate shares, percent of class. 13D and 13G use different XML element names for the same facts; GovGreed's parser handles both families and resolves tickers via the SEC's CIK mapping.

SEC EDGAR · Schedule 13D / 13G

Activist 13D Tracker: Who's Building Stakes — and Who Bought First

Q: What is a Schedule 13D filing?

When an investor crosses 5% ownership of a public company's stock WITH intent to influence control — board seats, strategy changes, a sale — they must file a Schedule 13D with the SEC within 5 business days. It is the loudest public signal that an activist campaign is starting. A 13G is the passive version: same 5% threshold, no intent to influence.

When an investor crosses 5% of a public company with intent to shake it up, they have five business days to tell the SEC on a Schedule 13D. GovGreed parses every one from EDGAR's structured XML, weekly: 41,224 filings since January 2025, 6,598 of them activist.

Then we ask the question no other tracker asks: who was already positioned? In roughly 180 cases, at least one member of Congress disclosed buying the same stock in the 90 days before the activist's filing landed.

41,224

13D/13G Filings

Jan 2025 → today

6,598

Activist 13Ds

intent to influence

5,216

Unique Tickers

6,190 filers

180

Congress Bought First

≤90 days before the 13D

Who Was Positioned First

Activist 13Ds where members of Congress disclosed purchases of the same ticker in the 90 days before the filing. Buy counts are deduplicated STOCK Act disclosures; the member list shows who was buying.

Correlation is not coordination. Members of Congress trade thousands of tickers, and activists target widely-held companies — overlaps will occur by chance. We publish every case with its dates so you can judge the timing yourself, and we allege nothing.

13D Filed	Ticker	Activist	Stake	Congress Buys (≤90d)	Members Buying

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Recent Activist 13Ds

The newest activist filings and amendments in the last 90 days — issuer, lead filer, and disclosed stake.

Filed	Form	Ticker	Issuer	Lead Filer	% of Class

The Most Active Activists (2025–2026)

Filing counts include amendments (13D/A). Verified 2026-07-14.

Filer	Activist Filings	Distinct Tickers	Known For
Saba Capital Management, L.P.	217	45	Closed-end fund campaigns
RA Capital Management, L.P.	58	21	Biotech
GAMCO Asset Management Inc.	58	31	Value / media
ORBIMED ADVISORS LLC	36	18	Healthcare
Tether Holdings, S.A. de C.V.	26	5	Crypto-adjacent stakes
Starboard Value LP	24	10	Board campaigns
John C. Malone	23	7	Liberty media complex

13D vs 13G: The Two-Letter Difference That Moves Stocks

Both forms fire at the same trigger — crossing 5% ownership of a public company's shares. The difference is intent. A Schedule 13G says “passive investor, no agenda.” A Schedule 13D says the opposite: the filer reserves the right to push for board seats, strategy changes, or a sale — and has five business days to say so publicly. That is why 13Ds are the loudest opening move in activist investing, and why target stocks often reprice on the filing itself.

How GovGreed collects it

Weekly, from the primary source. SEC EDGAR full-text search, parsing the structured XML inside every filing — issuer CIK, lead reporting person, aggregate shares, percent of class.
Both form families, correctly. 13D and 13G use different XML element names for the same facts; naive parsers silently drop one family. Ours handles both.
Tickers via CIK. Issuers resolve to tickers through the SEC's company mapping — 5,216 distinct tickers so far.
The congressional cross-reference uses deduplicated STOCK Act purchases (GovGreed's 103K-trade dataset), matched by ticker and window.

Frequently Asked Questions

What is a Schedule 13D filing?

The SEC disclosure required within 5 business days of crossing 5% ownership of a public company with intent to influence it. The passive equivalent (no intent) is a 13G.

Why do 13D filings matter to traders?

They mark the public start of activist campaigns — a sophisticated investor announcing serious capital behind a change thesis. Targets often reprice on the news, which makes who was positioned before the filing the interesting question.

Which activists file the most?

Saba Capital (217 activist filings in our window), RA Capital (58), GAMCO (58), OrbiMed (36), Tether Holdings (26), Starboard Value (24) and John Malone (23).

Did Congress really buy before activists filed?

In ~180 cases since January 2025, at least one member disclosed a purchase of the ticker within the 90 days before an activist 13D. Every case is listed above with dates and names. Overlap can be chance; we publish it so you can judge.

How current is the data?

The collector runs weekly against SEC EDGAR; this page reads live from the database on every load. Static text verified 2026-07-14.

About this data. Beneficial-ownership filings are collected weekly from SEC EDGAR and parsed from each filing's structured XML; congressional purchases come from deduplicated STOCK Act disclosures. Filing counts include amendments. "Stake" reflects the lead reporting person's disclosed percent of class at filing. Live figures re-read from the database on every page load.

Not financial advice. All data from public federal disclosures. GovGreed reports disclosed financial information and does not allege that any person violated any law.