How we measure things

For each insider we take every open-market purchase disclosed on SEC Form 4 (transaction code P) that carries a per-share price, and measure the change from that price to the live share price. The card figure is the simple average of those changes over the purchases filed in the trailing 12 months; when an insider has no priced purchase in that window we fall back to all disclosed purchases on record and label the figure “all time”. “In profit” counts purchases whose live price is above the purchase price.

Excluded: sales, option exercises, stock awards, 10b5-1 plan transactions, gifts, and filings without a per-share price. Purchases in foreign ordinary shares quoted as ADS are a known distortion and are being corrected at the data layer.

A stock qualifies for a bubble when a single insider’s open-market purchases on a single day total $250,000 or more (Form 4 code P, unplanned). Bubble size scales with the total dollars bought in the selected window. Colour compares the current price with the VWAIP — the volume-weighted average price the insiders paid over the window: green when the stock trades above what insiders paid, red when it trades below (i.e. cheaper than the insiders paid). A gold ring marks a filing that appeared since your last refresh.

The exchange filter classifies a listing by its exchange (NYSE, NASDAQ, AMEX and OTC as U.S.; TSX, TSX-V, CSE and NEO as Canada; XETRA and the Frankfurt, Stuttgart and Munich floors as Germany). German rows come from Directors’ Dealings notifications under Article 19 MAR, the EU equivalent of Form 4. Sector chips map the market-data sector and industry onto six groups: Energy; Mining (Basic Materials companies in metals, mining and coal); Biotech & Pharmaceuticals (Healthcare companies in biotechnology and drug manufacturing); Technology; Consumer Staples (Consumer Defensive); Financials (Financial Services).

Members of Congress disclose trades on Periodic Transaction Reports (PTRs) under the STOCK Act. PTRs report amounts as ranges — for example $15,001–$50,000 — not exact figures. Everywhere we size or sum congressional trades we use the midpoint of the reported range ($32,500.50 for that example). Bubble size is the sum of midpoints for the member’s trades in the period; colour is net buying (green) or net selling (red) on the same basis. “Days to disclosure” is the average gap between a trade’s transaction date and the date the PTR was filed.

Source data is the House and Senate clerks’ disclosures via our market-data provider, refreshed nightly. Portraits are the official congressional photographs (public domain) keyed by Bioguide ID. Party and state come from the public @unitedstates legislator roster.

Portfolios come from each manager’s quarterly SEC Form 13F-HR, which reports U.S. long positions at quarter-end and is filed up to 45 days later; we keep the latest six quarters. The trailing-12-month performance is the value-weighted return of those disclosed long positions, rebalanced at each filing date: each quarter-to-quarter leg weights every position by its value at the start of the leg and measures the change in its filing-implied price (reported value ÷ shares); the final leg runs from the latest quarter-end to today at live prices. A position that first appears at the end of a leg was bought during it, so its purchase price is estimated as the period average of the start-of-leg and end-of-leg prices and it is weighted by that estimated cost. Legs compound, the earliest is pro-rated to the part of it inside the last 365 days, and the calculation uses each filer’s 100 largest positions by value (the covered share of the portfolio is shown on every leg). Puts, calls and positions that cannot be priced at both ends are excluded.

Suppression. Concentrated or near-empty portfolios produce meaningless figures, so the performance line is blank for portfolios under $100 million or with fewer than 4 positions, and for managers with no current 13F filings (defunct or deregistered funds are shown with no portfolio rather than an invented one). “Insiders agree” marks holdings where corporate insiders have made open-market Form 4 purchases in the last 90 days. Category tabs (Growth, Value, Short Sellers, Long-Term) are editorial classifications, not measurements.

A 0–99 composite of the buying itself (size versus market cap, cluster, seniority, stake growth, aggregate insider ownership), sector strength, management tone, trading momentum, insider calibre and share dilution, less a litigation deduction; recomputed daily. Green badges mark scores of 75 and above, gold 50–74. Full definition on the score explainer.

Insider Buying is a publisher, not an investment adviser. Every figure is historical and factual, traceable to a public filing or a licensed market-data feed, and provided for informational purposes only. Historical patterns do not predict future results, and nothing on this site is a recommendation to buy or sell any security.