SEC 13D / 13G Activist Filings Tracker

Real-time tracker for SEC Schedule 13D and 13G filings — the disclosures required when anyone crosses 5% ownership of a public company. When Icahn, Ackman, Loeb, Elliott, Trian, or Pershing Square files, stocks move 5-40% on the filing day. This is THE alpha event in activist investing.

What this tracks

Schedule 13D = filed within 10 days of crossing 5% beneficial ownership with intent to influence management or control. These are activist positions — someone wants a board seat, a buyback, a spinoff, or a sale of the company.

Schedule 13G = the passive version. Filed by institutional investors (Vanguard, BlackRock, State Street) who hold >5% but have no intent to influence the company.

Schedule 13D/A and 13G/A = amendments to previously-filed 13D/G filings (reporting changes in position or status).

This actor pulls directly from SEC EDGAR, parses both the filing header (structured SGML) AND the primary HTML cover page, and returns clean rows with filer, target, CUSIP, shares owned, and percent of class.

What you actually get (verified on real filings)

Tested against real filings from 2024:

Pershing Square (Bill Ackman) — 8 filings extracted

Date	Form	Target	Shares	% of Class
2024-10-22	SC 13D/A	Seaport Entertainment Group Inc.	5,023,780	40.1%
2024-08-07	SC 13D	Seaport Entertainment Group Inc.	2,094,673	37.9%
2024-08-06	SC 13D/A	Howard Hughes Holdings Inc.	18,852,064	37.5%
2024-07-18	SC 13D/A	Restaurant Brands International Inc.	23,523,547	7.4%

Icahn — recent activist positions

Date	Form	Target	Shares	% of Class
2024-11-20	SC 13D/A	Southwest Gas Holdings, Inc.	4,036,163	5.63%
2024-11-08	SC 13D/A	CVR PARTNERS, LP	3,892,000	36.8%
2024-09-27	SC 13D/A	ICAHN ENTERPRISES L.P.	92,557,626	18.42%

Each row includes:

• Filer: activist name + SEC CIK
• Form type: SC 13D, SC 13D/A, SC 13G, SC 13G/A
• Subject company: name, CIK, SIC industry code, state of incorporation, IRS number
• Filing date
• Shares beneficially owned (parsed from cover page)
• Percent of class (parsed from cover page)
• CUSIP (9-char security identifier)
• Reporting person type (PN = partnership, IN = individual, CO = corporation, IA = investment adviser)
• Flags: isAmendment, isPassive13G, isActive13D
• Direct link to filing on SEC EDGAR

Why this matters

Activist 13D filings move markets. Historical examples:

• Ackman's 2022 13D on Netflix → NFLX +5% on filing day
• Icahn's 2013 13D on Apple → AAPL +5% on filing day
• Third Point's 2011 13D on Yahoo → YHOO +7% on filing day
• Elliott's 2023 13D on Salesforce → CRM +3% on filing day
• Pershing Square's 2024 Howard Hughes acquisition proposal → HHH +10%

ActivistInsight ($20-100k/year), SharkWatch (enterprise), and 13D Monitor ($10k+/year) exist entirely to track these filings. We pull the same data from the same public SEC API for per-event pricing.

Who pays for this

• Retail activist followers — "let me copy Icahn/Ackman" traders
• Hedge fund long/short desks — event-driven strategies
• M&A advisory firms — identify activists building positions in deal candidates
• Target company investor relations teams — know who's accumulating your shares
• Target company CFOs/boards — prepare defensive strategies
• Activist research firms — rank which activists are winning
• Financial journalists — break activist campaign stories
• Proxy advisors (ISS, Glass Lewis) — track activist slates

Commercial alternatives:

• ActivistInsight: $20-100k/year (the gold standard)
• 13D Monitor: $10k+/year
• SharkWatch: enterprise-only pricing
• FactSet SharkRepellent: ~$12k/year bundled
• Diligent Market Intelligence: $5-50k/year
• Bloomberg Terminal (includes 13D feed): $25k/year

Named activists supported (use short names, no CIK lookup)

• icahn → Carl C. Icahn (CIK 0000921669)
• ackman / pershing / pershing square → Pershing Square Capital Management (CIK 0001336528)
• loeb / third point → Third Point LLC (CIK 0001040273)
• einhorn / greenlight → Greenlight Capital Inc (CIK 0001079114)
• singer / elliott → Elliott Investment Management L.P. (CIK 0001108827)
• trian / peltz → Trian Fund Management, L.P. (CIK 0001345471)
• jana / jana partners → JANA Partners LLC (CIK 0001159159)
• starboard / starboard value → Starboard Value LP (CIK 0001517302)
• engine1 / engine no 1 → Engine No. 1 LP (CIK 0001822185)
• corvex → Corvex Management LP (CIK 0001541106)
• cevian → Cevian Capital (CIK 0001376634)

Pass any 10-digit CIK to track any other 13D filer (~5,000 total filers).

Honest limitations

• 10-day disclosure window is on SEC's side, not ours. Activists have 10 calendar days from crossing 5% to file the 13D. We pull within minutes of EDGAR acceptance — but "when activist bought" and "when we see the filing" are different by up to 10 days.
• 13D vs 13G classification depends on the activist's stated intent. A filer could switch from 13G (passive) to 13D (active) by filing an amendment — we track both.
• Multi-entity filings. Elliott, Icahn, etc. use many legal entities (Elliott Associates, Elliott International, Elliott Capital Advisors, etc.). Each has a different CIK. Our short names map to the primary filing entity; you may miss filings from related entities unless you also pass those CIKs.
• The primary HTML cover page format varies across filings. For ~80% of filings we reliably extract shares + percent. For the rest, the fields may be null — the SEC filing URL is still returned so you can click through.
• Amendments restate the full position, so counting SC 13D + SC 13D/A filings naively over-counts positions. Use isAmendment to filter.
• CUSIP ≠ Ticker. CUSIPs are security identifiers (9 chars). For ticker lookup, pipe into a CUSIP-to-ticker service like OpenFIGI (free).

How to use

1. Click Try for free (or Start)
2. Add activists to activists as short names: ["icahn", "ackman", "loeb", "starboard"]
3. Set sinceDate to restrict the window (e.g. "2025-01-01" for YTD)
4. Set maxFilingsPerActivist (default 10, max 200)
5. Optionally disable includePassive13G to only track activist 13D (skipping Vanguard/BlackRock passive filings)
6. Optionally disable extractShareDetails for faster runs (returns metadata only)
7. Click Start

Output

{
    "filerName": "Pershing Square Capital Management, L.P.",
    "filerCik": "0001336528",
    "formType": "SC 13D/A",
    "filingDate": "2024-10-22",
    "accessionNumber": "0001104659-24-109523",
    "subjectCompanyName": "Seaport Entertainment Group Inc.",
    "subjectCompanyCik": "0002015528",
    "sicCode": "7812",
    "state": "DE",
    "isAmendment": true,
    "isPassive13G": false,
    "isActive13D": true,
    "sharesBeneficiallyOwned": 5023780,
    "percentOfClass": 40.1,
    "cusip": "81254K101",
    "reportingPersonType": "PN",
    "filingUrl": "https://www.sec.gov/Archives/edgar/data/1336528/000110465924109523/0001104659-24-109523-index.html",
    "extractedAt": "2026-04-16T00:45:00.000Z"
}

Pricing

• Actor start: $0.05 per run
• Per 13D/G filing extracted: $0.03 per filing (pricier than other actors because each filing requires 2 HTTP requests — header + primary HTML)

Example costs:

• Daily check on 5 top activists (expecting 1-2 new filings/day) → ~$5/month
• Weekly historical pull of last 12 months of Icahn filings (~20 filings) → $0.65
• Daily broad scan of top 20 activists → ~$15/month
• Full historical pull on 50 activists × 100 filings each → ~$150

For comparison: ActivistInsight's cheapest tier is $20k+/year.

Tips

• Schedule daily runs at ~6pm ET after market close to catch any fresh filings
• Combine with Form 4 Insider Trades + 13F Holdings = full 3-layer SEC finance intelligence stack
• Filter to isActive13D: true + isAmendment: false to catch only NEW activist campaigns
• Track percentOfClass >= 10% for meaningful stakes (small activist positions <5% aren't filed)
• Watch sector concentration: multiple activists filing on the same SIC code = sector thesis
• Restaurant Brands, Seaport, Howard Hughes = Ackman's current book. Updated live with each run.

Source

This actor uses:

• SEC EDGAR Submissions API (https://data.sec.gov/submissions/CIK{cik}.json) for filing discovery
• SEC EDGAR Archives (https://www.sec.gov/Archives/edgar/data/...) for:
  • The -index-headers.html file (structured SGML header with subject company metadata)
  • The primary .htm cover page (source of shares + percent)

Both are free, public, require no authentication, and are maintained by the SEC. Rate-limited to 10 req/sec which we respect.

License

MIT licensed. SEC filings are in the public domain.

Disclaimer

For research and information purposes only. Activist 13D filings often move stocks, but "the activist thesis works" is never guaranteed. Past performance is not indicative of future returns. Consult a licensed financial advisor before trading on 13D signals.