S&P 500 Trends After Midterm Elections: Historical Market Insights

As the United States approaches its upcoming midterm elections, investors are closely monitoring the stock market's potential reaction. History reveals that the S&P 500 index generally experiences positive returns after both midterm and presidential elections, regardless of which political party gains control.

A detailed analysis by CNBC, covering election outcomes from 1980 through 2024, shows modest gains for the S&P 500 in the short term following elections. The index typically rises by an average of 0.2% after one day and one week, and about 1.1% after one month. More notably, the one-year performance following midterm elections averages a 13.7% increase, with presidential elections yielding a similar 13.8% gain. Positive returns occurred in 91% of those election years, and the S&P 500 posted gains after every midterm election from 1982 through 2022.

While short-term market reactions can be less consistent, especially after presidential elections where returns have occasionally shown slight negative averages in the immediate days and weeks, the overall trend leans bullish. Ryan Detrick, chief market strategist at Carson Group and CNBC contributor, pointed out that market anxiety tends to ease after the elections, often leading to stronger performance.

One significant pattern is the market's preference for divided government. When one party controls the White House and the other holds at least one chamber of Congress, the S&P 500 has experienced an average 15% gain over the following year. This scenario produced positive returns in 14 out of 15 cases examined. In contrast, elections that resulted in one party holding both the executive branch and Congress saw average gains of 11.5% over the year, reflecting somewhat more cautious investor sentiment.

Detrick explained that markets often react unfavorably to a sweeping victory by either party, as such outcomes may lead to excessive spending or concentrated political power. An example includes past midterms (1986, 1990, 2006) when Democrats controlled Congress while a Republican occupied the presidency. In those instances, the S&P 500 experienced a small decline on election day but rebounded with a 3.4% increase after one month and a 10.9% gain after one year.

It is important to recognize that election results do not operate in isolation. Broader economic trends, Federal Reserve policies, and corporate earnings exert substantial influence on market performance. For example, after the 2000 elections, the S&P 500 fell 22.1% in the following year amid the dotcom crash, marking the worst post-election outcome since 1980. On the other hand, the index soared 38.3% after the 2020 elections, reflecting a strong rebound from the pandemic-induced downturn.

Monetary policy plays a crucial role as well. The 2018 midterms saw stock declines when Democrats took control of the House during President Donald Trump's tenure. However, the Federal Reserve's decision to raise interest rates four times that year contributed significantly to that decline. Despite a 6.2% drop in the S&P 500 for 2018, the market recovered with an 11.7% gain one year after the election.

Looking ahead, artificial intelligence (AI) developments are a major focus for investors. Continued progress in AI and sustained economic growth could support ongoing market strength. Yet, a Democratic sweep of both the House and Senate might slow AI infrastructure expansion, potentially leading to reduced investment in the sector. Other factors adding uncertainty include rising global bond yields, a debt crisis in France, and tensions involving Iran, which could escalate depending on geopolitical decisions post-election.

Jim Reid, Deutsche Bank’s global head of macro and thematic research, cautioned that seasonal market trends may not override current risks related to geopolitics and economic conditions. Despite this, historical patterns suggest the possibility of a year-end rally in the S&P 500 following the midterms, though the market remains influenced by AI innovation, Federal Reserve moves, and global events.

In summary, while midterm elections often bring volatility, the S&P 500 has consistently shown resilience and growth in the year following these political milestones. Investors should consider election outcomes alongside broader economic indicators and sector trends when assessing future market directions.