Methodology

The calculation

Estimated excess return

1. Entry. The first closing price on or after the disclosed transaction date. If the transaction date is not a trading day, the entry rolls forward to the next session — never backward to a price that existed before the trade.
2. Exit. The most recent closing price held for that ticker, as of 2026-08-27.
3. Ticker return = (exit − entry) ÷ entry.
4. Benchmark return = the same calculation on SPY, measured on the ticker’s own entry and exit dates — the identical window, not SPY’s latest close.
5. Excess return = ticker return − benchmark return.

The same inputs always produce the same figure. The exit is the price data’s as-of date rather than “today”, which is what makes a published figure reproducible from the record.

Financial Modeling Prep — end-of-day closes · as of 2026-08-27 · updated daily

Known limits

What this figure is not

• Disclosed amounts are ranges, not position sizes. Congressional filers report a bracket such as $1,001–$15,000. The excess return is a per-share measurement and is not weighted by how much was actually bought or sold, because that quantity is not disclosed.
• Execution prices are not disclosed. The entry uses a closing price, not the price the filer actually paid. The real execution price is not in the public record.
• The figure is an arithmetic difference of two simple returns, so it can exceed ±100%. A ticker that fell 53% while the benchmark rose 50% shows an excess return of −103%. That is the arithmetic working, not an error.
• The entry rolls forward. Weekend and holiday transaction dates enter at the next session’s close.
• Coverage is not total. Where no price series is held for a ticker, or a close is missing at either end of the window, the cell renders a dash whose label reads “no price data” followed by which of those applies. It is never zero and never estimated. On the current corpus that is 38 transactions of 1,139: 21 whose filing names no ticker, 9 whose price history begins after the transaction date, and 8 whose symbol the price source does not cover at all.
• A delisted stock is priced to its LAST available close, and the cell says so. The exit leg is the newest close the price source holds for that ticker. For a company that stopped trading — acquired, delisted, renamed — that close can be months or years old, and the figure then measures the period up to that date rather than up to today. Two transactions in the current corpus are in this state; each cell names its own exit date rather than presenting an old return as a current one.
• Record identity is the whole record within a chamber, so two congressional lots identical in every disclosed field are collapsed into one. A filer who genuinely made two identical transactions on the same report appears once.

Disclosure dates

Which date a card shows

House disclosure dates come from the House Clerk’s own annual disclosure index, joined to each record by the document identifier in its filing link — not from the data vendor, whose published date runs later than the statutory filing date. Senate dates are the vendor’s. The full statement, including what is measured and what is not, is on about the data.

U.S. Senate eFD + U.S. House Clerk — Financial Disclosure, via Financial Modeling Prep; House disclosure dates from the House Clerk annual index