Congressional purchases, on average, lose to the market. The baseline alpha is -2.40% at 180 days. But one filter — cross-chamber bipartisan cluster buys — produces +6.22% alpha vs. SPY at 180 days across 503 validated signals. We show every step.
If you read most coverage of congressional trading, you'd think Congress is a superhuman stock picker. STOCK Act disclosures get publicized when Pelosi buys NVDA. The Capitol Trades site shows trade-by-trade returns that often look spectacular. The narrative is: members of Congress have inside information about regulation, contracts, hearings, and they're using it to beat the market.
The data tells a different story.
We analyzed every congressional stock purchase with enough subsequent price history to measure — 10,428 of them, drawn from the full corpus of more than 30,000 STOCK Act filings (2018–2026) across 436 members of the House and Senate. We focus on purchases because sales, sale-partials, and exchanges are often liquidity-driven rather than information-driven.
Across those 10,428 purchases, the average alpha vs. the S&P 500 at 60 days is -0.96%. At 180 days, it's -2.40%. Congressional purchases, in aggregate, underperform the market.
That's the naive answer, and it surprises people. Members of Congress are not, in aggregate, good stock pickers. They have other priorities (legislative work, fundraising, district service), they're not full-time investors, and the diffuse pool of 436 disparate decision-makers produces results worse than the index.
So why does Signal Congress exist? Because the aggregate hides everything that matters.
When you look at the 10,428 trades, the variance is enormous. Some trades return +200%. Others return -80%. The average masks a tremendous dispersion. The question isn't “do congressional trades beat the market?” — the answer is no. The question is “which congressional trades beat the market, and can we identify them in advance?”
That's where the bipartisan clustering filter comes in.
A cluster is defined as two or more members trading the same ticker within a 30-day window. A cluster is bipartisan if both Republican and Democratic members are present. A cluster is cross-chamber if both House and Senate members are present.
The intuition is simple. Coordinated buying across party lines is rare. If a Democrat from a banking committee and a Republican from a defense committee independently arrive at the same trade within 30 days, the signal is unlikely to be partisan ideology or sector-specific news. It's more likely that both arrived at the same thesis independently — whether from public policy signals, sector analysis, or committee-relevant legislative activity.
The question is whether this intuition shows up in the data. It does.
Apply progressively tighter filters and the picture changes significantly.
Read these together with two questions:
(1) Is there a strategy that beats baseline at 180 days? Yes. Cross-chamber bipartisan trades produce +6.22% alpha at 180 days — an 8.6-percentage-point improvement over the negative baseline. Win rate at 180d is 50.7%, meaning roughly 51 of every 100 cross-chamber bipartisan purchases outperform the S&P 500 over six months.
(2) Is there a strategy that wins consistently at 60 days? No. Every filter we tested produces only modest improvements at the 60-day horizon. The cross-chamber filter shows +1.30% (vs. -0.96% baseline) and a win rate that barely clears 50%. The edge in magnitude does not appear until you extend the holding period.
Conventional wisdom holds that insider information should produce immediate price impact. If a senator on the Banking Committee buys regional bank stocks two weeks before the Fed announces a rate cut, you'd expect to see outperformance over the next 30-60 days.
The data doesn't support this for congressional trades. The 60-day alpha for every filter we tested is small (under +1.4%). The 180-day alpha for the cross-chamber filter is nearly 5x larger.
Individual high-conviction members reinforce this: their edge tends to widen as the holding period lengthens rather than showing up immediately. The cross-chamber bipartisan filter behaves the same way at the strategy level — a weak edge at 60d, a strong edge at 180d.
If you'd bought every congressional purchase, you'd be behind the market: 10,428 trades, average alpha -0.96% at 60d and -2.40% at 180d.
If you'd bought only the cross-chamber bipartisan cluster signals, you'd have made 503 trades — under 5% of the available universe — and beaten the S&P 500 by +6.22 percentage points on average at the 180-day mark.
The bipartisan-and-cross-chamber filter reduces the trade count by about 95%. The question is whether the 503 remaining signals are worth the discipline of ignoring the other ~9,900.
At +6.22% 180d alpha vs. -2.40% unfiltered, we believe they are.
This is what Signal Congress is built around. Every feature in the platform — the leaderboard, the conviction score, the cluster strength score, the AI thesis summaries, the compliance watch — exists to help you find, validate, and act on cross-chamber bipartisan signals. If you do not see one, you are looking at noise, not signal.
Honest backtesting includes its limitations.
Daily-updated cross-chamber bipartisan clusters, conviction-scored trades, and cascade alerts — updated daily from the official STOCK Act filings.