Would copying Congress have beaten an index fund?

Every few months someone pitches a fund or an app that copies the stock trades members of Congress disclose. I work at Equibles, a financial data company, and we tested the idea on 17,859 stock disclosures filed under the STOCK Act from January 2020 to August 2025, buying at the first close after each filing became public.

A year later, the typical purchase trailed the S&P 500 by 5.4 percentage points, and only 43% of purchases beat the index. The stocks members sold lagged too, by 6.4 points, so their sales weren’t much of a warning either. Even pretending you could buy the day after the trade itself, ignoring the reporting delay, purchases still trailed by 5.7 points.

This year looks the same. Of members’ 2026 purchases we could score, 39% were ahead of the S&P 500 from the trade date to October 26.

The lesson I took from it is an old one for this forum: following someone else’s picks, even people with a front-row seat, didn’t beat simply owning the index. The study, with the method: https://equibles.com/research/what-happens-after-congress-buys-or-sells-a-stock-evidence-from-17-859-disclosures