Members of Congress disclose their trades, with a lag of up to forty-five days. We tested whether copying their disclosed purchases on the day they became public would have beaten the market. It did, at about 34.8 percent a year against 12.3 for the index. The qualification is that one filer and a sample of 77 trades carry the result.
Members of the United States Congress are required to disclose their securities trades. The disclosures arrive with a lag of up to forty-five days, long after the trade itself. The question this note asks is narrow and testable: if you simply copied those purchases on the day they became public, respecting the lag, would you have beaten the market. The answer over the last five years is yes, but with a heavy qualification that the headline hides.
The easy read: Congress beats the market, so copying members is a structural edge available to anyone willing to read the filings.
Our reading: the aggregate number is carried by one member and a small set of trades. It is an interesting study of how slowly public information is absorbed, not a robust, diversified strategy. We present it as evidence on a question, not as a recommendation.
This note is not about any individual or any party. It is about a measurable question: how much information is left in a trade by the time the public is allowed to see it.
The academic starting point is Ziobrowski and co-authors (2011), who found that the common-stock investments of members of the U.S. House of Representatives earned abnormal returns. The popular version of the claim is that members trade with an informational advantage tied to their committee work and legislative knowledge. Whatever the source, the testable part is simpler. The trades become public, with a delay, under the STOCK Act. If those disclosures still predict returns after the delay, then public information is being absorbed slowly, which is the same family of effect as the drift after an earnings report.
The forty-five-day lag is the crux. By the time a disclosure is filed, the trade is old news in the literal sense. For copying to work, the move the member was positioned for has to keep going after the public learns of it. That is a strong condition, and it is exactly what the test checks.
If a disclosed purchase still earns excess return after the public sees it, the market is slow to price information that is, by then, fully public.
We took the disclosed purchases of three named members from the public filings, kept only ordinary stock purchases, and entered each at the closing price on the date the trade became public, the notification or filing date, never the trade date. Each position is equally weighted and held for 252 trading days. Options are copied as the underlying stock. We compare the resulting portfolio, per member and combined, to a buy-and-hold position in the S&P 500 over the same dates.
The sample is 77 disclosed purchases across 18 tickers, which is small. Disclosed amounts are ranges, so positions are equally weighted rather than dollar-weighted. Sales are not shorted, dividends and trading costs are ignored, and the window begins when daily price coverage starts in 2021. A few non-index tickers use adjusted prices from a public source. This is a study of disclosed purchases, not a complete or investable replication of any person's portfolio.
Copying every disclosed purchase produced a portfolio that compounded to roughly four and a half times its starting capital over the five years, against about 1.8 times for the S&P 500. The line is not smooth: it leads the index for most of the period and takes a real drawdown in the 2022 decline. The individual member lines show where the return came from, and they are far from uniform.
Annualising the returns makes the concentration impossible to miss. The most active member's disclosed purchases compounded at about 31.5 percent a year. The second roughly matched the market at 11.4 percent. The third, with a single disclosed purchase in the sample, lagged. The combined portfolio's 34.8 percent is therefore not the wisdom of Congress; it is largely the record of one prolific filer over a five-year bull market in a concentrated set of large technology names.
Copying disclosed Congressional purchases beat the market over the last five years, even after respecting the forty-five-day lag. That is a genuine and interesting result about how slowly public information is absorbed. It is not, on this evidence, a robust strategy. The edge rests on one member and 77 trades, it carried a market-sized drawdown, and it ran through a period that rewarded concentration in a few large names. We report it as what it is: a small, honest study of a much-discussed question.
The filing is public. Whether the edge survives the publishing is the test.
This document has been prepared by Iron Hall Capital for informational and educational purposes. Its content does not constitute personalised investment advice, a recommendation to buy or sell financial instruments, a public offering, or a solicitation to subscribe to any financial product. The opinions and readings reflect Iron Hall Capital's judgement at the date of publication, are based on data considered reliable but not independently audited, and may be revised without notice.
The results shown are from historical simulations on past data. Backtested performance is hypothetical, is computed with the benefit of hindsight, does not reflect trading costs, financing, taxes, slippage or the market impact of real execution, and is not a reliable indicator of future results. Where a data series was not available, an equivalent real series has been substituted and labelled as such in the text. Where a method ignores costs or makes a simplifying assumption, this is stated. Markets can move sharply and without warning.
The author and Iron Hall Capital may hold, have held, or come to hold positions in the instruments referenced. Any reproduction, in whole or in part, requires written authorisation.
Iron Hall Capital · A private investment office · June 2026