S&P 500 Logged Gains After 19 Midterms, Averaging 15.1%

The S&P 500 recorded gains in each of 19 12-month periods after U.S. midterm elections dating to 1950, offering historical context as voters cast ballots Tuesday, Nov. 3.

The periods averaged a 15.1% gain, but individual results varied widely. The record describes past performance and does not establish how the index will move after the 2026 election.

A broader tally of post-midterm 12-month periods dating to 1938 found gains in 95% of cases, in a review covering a longer historical sample.

A separate midterm-cycle comparison tracks 21 periods from November of an election year through the following June. Each period was positive, with an average gain of 16.6%; its measurement window differs from the 12 months after each election.

Treasury yields, inflation, fiscal conditions and Federal Reserve policy could affect valuations and earnings. Investors are also weighing whether spending on artificial intelligence will generate returns sufficient to support the investment.

Changes in congressional control may affect fiscal policy, regulation, trade and government spending, with potential consequences for technology, defense, industrial and financial companies, as well as Treasuries and the dollar. Economic and financial conditions may have more influence on markets than party control alone.