The U.S. Senate is poised to vote to end the record-breaking 40-day government shutdown, potentially bringing relief to federal workers and the economy. For investors nervous about the political gridlock, history suggests the market’s real move comes after the reopening—and it's typically a strong one.

S&P 500 Has Averaged A 12.3% Gain After Past Shutdowns

Historical data analysis of past government shutdowns shows that the S&P 500 has rallied significantly in the 12 months following the end of the political stalemate, posting an average gain of 12.3%.

The analysis, highlighted by Ryan Detrick of Carson Group, reveals a powerful bullish precedent. In all the instances since 1976, the S&P 500 was positive 20 out of 22 times one year after the government reopened, representing a 91% win rate for investors.

This optimistic long-term trend stands in stark contrast to the market’s performance during the shutdowns. Detrick's data shows the median S&P 500 return during the shutdowns themselves was a mere ...