Methodology
The Insider Ledger tracks public SEC filings — insider transactions (Form 4), activist stakes (Schedule 13D), and quarterly institutional holdings (Form 13F) — for a fixed watchlist of influential investors, founders, and corporate capital allocators. Every week an automated pipeline pulls new filings from SEC EDGAR, normalizes them into events, scores them, and writes the edition; a written analysis explains what each action may reveal about the company or sector. Every claim cites the filings it comes from.
The watchlist
Ten institutions whose quarterly holdings we follow — Berkshire Hathaway, Pershing Square, TCI Fund Management, Coatue, Altimeter, Appaloosa, Baupost Group, Fundsmith, Himalaya Capital, and Tiger Global — and seven companies whose executives' trades we follow: NVIDIA, Microsoft, Alphabet, Meta, Amazon, AMD, and Arm. The Investors page lists everyone with their tracked activity; Stocks covers every company that has appeared in a tracked filing.
The signal score
Each stock's score adds up what committed capital reveals and subtracts what weakens it. The components and weights:
| Component | Weight |
|---|---|
| Capital committed (insider buys, new or increased institutional positions, activist stakes; scaled against $10M) | up to +20 |
| New institutional position in the last 120 days | +15 |
| Consecutive quarters of accumulation by the same fund (+5 per quarter) | up to +15 |
| Independent watchlist holders (+5 per holder beyond the first) | up to +15 |
| Any open-market insider buying in the last 90 days | +10 |
| Activist 13D filed in the last 180 days | +10 |
| Average filing delay over 30 days | −10 |
| Crowding: six or more watchlist holders | −15 |
| All insider buying is plan-based (10b5-1) | −20 |
Scores top out around +85 and can go negative. Two components from the underlying research — valuation and price momentum — are deliberately weighted at zero until the site has a market-data source; the score reflects filing behavior only, not price. Scores rank stocks against each other as a research queue. They are not predictions, price targets, or advice.
What counts as signal
Open-market purchases, repeated accumulation across quarters, and several independent investors reaching the same conclusion are strong signals. Scheduled 10b5-1 plan trades are weak ones. Insider sales are treated as weakly informative in the analysis because they often reflect taxes, diversification, or liquidity rather than a view on the business — they appear in the data and in each stock's net insider value, but selling alone never raises a score.
Coverage and limitations
Filings surface with the lags the SEC allows: Form 4 within two business days of the trade, Schedule 13D within five business days of crossing 5%, and Form 13F up to 45 days after quarter end. History begins with the Q1 2026 institutional baseline (filings from January 2026 onward).
Deliberate boundaries of the current pipeline: only non-derivative, open-market Form 4 transactions are captured — option exercises, grants, and derivative-table entries are excluded entirely, not scored as noise. Only original 13F-HR reports are processed (amendments and restatements are not). Coverage is US filings only. 13F reports also exclude short positions, most derivatives, and non-US holdings by their nature, so we cannot see an investor's hedges, cost basis, or private portfolio.
The output is a research queue, not a set of recommendations — see the disclaimer.