The S&P 500 has risen in every 12-month period after a midterm election since 1950. But high valuations leave less room for error, even if earnings growth and divided government support another gain.
The S&P 500 Shiller CAPE ratio stood at about 41.16 at the end of September 2026. That is near its second-highest level. The reading puts a long-running post-election record up against a market with little room for disappointment.
Since the index took its current 500-company form in 1950, it has risen in every 12-month period after a U.S. midterm election. Investors should treat that history as context, not a forecast, especially when stocks trade at a steep premium to much of their past.
In midterm election years, the S&P 500 has historically fallen about 15% from its high to its low before often recovering. Wells Fargo Investment Institute's observation describes an intra-year pattern, not a guarantee of gains after Election Day.
A record with limits
There have been 19 midterm elections since 1950. The S&P 500 was higher 12 months after every one, with an average return of roughly 15%. Fidelity Investments' broader historical series includes the index's predecessor. It found gains in 95% of the 12-month periods after midterms since 1938 and an average return of about 14.5% in the calendar year after a midterm.
Those periods included difficult events, among them the Korean War and the 1973 oil shock. The record did not come only from calm markets. Robert W. Baird & Co. found a different pattern: the index gained an average of 32% in the year after its midterm-year low. That measure starts at the market bottom, not on Election Day. The fourth quarter has also been strong in midterm years, with an average S&P 500 gain of about 6.4%, according to an election-year Q4 analysis.
The pattern reaches further back, though that measure includes the S&P 500's predecessor. One possible reason: elections can ease some political uncertainty. Midterms also often give seats to the party outside the White House. That raises the prospect of divided government, which has generally coincided with stronger stock-market performance.
Citi says the risk premium associated with midterm uncertainty typically begins rising about 50 trading days before the vote and peaks in the final weeks, as investors weigh political uncertainty and the possibility of divided government.
Valuations raise the bar
History cannot erase the price investors pay for future earnings. The Shiller CAPE compares stock prices with inflation-adjusted earnings averaged over a decade. It is near its second-highest level. Market summaries put the reading at about 41.16 at the end of September 2026, after it peaked at 42.84 in June 2026.
Only late 1999 and early 2000 brought higher readings, before the dot-com bubble burst. High valuations do not tell investors when a decline will come or what will cause it. They do make the historical pattern less reassuring on its own.
The Buffett indicator offers another warning. It compares total U.S. stock-market capitalization with gross domestic product. In August 2026, it stood at roughly 235%, just below its all-time high of nearly 237%. Warren Buffett warned nearly 25 years ago that a reading approaching 200% meant investors were taking substantial risk.
The indicator is a broad comparison, not a precise timing tool. It cannot say whether stocks will rise or fall over the next year. The warning is clear.
Politics is only one input
The case for another post-election gain partly rests on earnings. Corporate profits are growing faster than valuations, and continued earnings growth could help keep a bear market at bay. That depends on earnings momentum holding up. If it fades, high prices may be harder to support.
At the time of the reported snapshot, the index was up around 13% in 2026. That gain does not settle what happens after the election.
Prediction markets then favored Democrats retaking the House. Kalshi put the odds at 91.4% and Polymarket at 93%. Both gave Democrats a 63% or higher chance of winning enough seats to control the Senate. Those figures reflect market-implied expectations, not election results.
Even if Republicans held the Senate, the analysis pointed to divided government in January 2027. An earlier market analysis tracked earnings forecasts alongside oil and Treasury yields. Political headlines compete with those forces in stock pricing.
The historical streak makes a reasonable case for expecting gains. It is not a reason to count on them. My view is that the S&P 500 can extend the pattern in 2027 if earnings keep outpacing valuation expansion and divided government emerges. Either condition could fail.
Midterm history belongs in the outlook, but it should not outweigh stock prices or companies' ability to deliver profits. Valuation ratios compare market prices with earnings or economic output. They show how expensive stocks look relative to those measures, not what returns will come next.
A high reading can persist while earnings grow. A lower one does not prevent losses. For investors, the distinction matters: valuation can warn that there is less cushion, but it cannot reliably time a market turn.
