S&P 500 likely to slip 18% in 2026 midterm year, August bottom

The S&P 500 is expected to experience an average intra‑year drawdown of about 18% this midterm election year, giving investors roughly a 70% chance of a correction before a typical rebound begins in August [1].

Historical pattern of midterm years

Since its inception in 1957, the S&P 500 has posted an average total return of just 1% in midterm election years, with 12 of the 17 midterms resulting in a correction of at least 10% [1]. The typical intra‑year slump averages 18%, meaning the index often falls sharply before stabilizing. The probability of such a correction in 2026 is roughly 70%, based on the same historical record.

Timing of the rebound and volatility

Research shows that the six‑month window after the November midterms (November through April) is the strongest segment of the four‑year presidential cycle, delivering an average 14% gain for the S&P 500 [1]. Market volatility also tends to peak just before voters head to the polls, then recedes once results are known [2]. This rhythm suggests that, despite a likely mid‑year dip, the index could start its recovery as early as August, aligning with the historical post‑election bounce.

Market implications for 2026

The anticipated correction coincides with heightened political uncertainty, as the party in power typically loses congressional seats, prompting concerns over fiscal, trade, and regulatory policy direction [1]. While Wall Street projects a 17% upside to 8,146 by year‑end, past median forecasts have missed by an average of 16 percentage points over the last four years, underscoring the difficulty of predicting outcomes in a volatile election environment [1].

What to watch

• Midterm election date (Nov 2026) – Market volatility historically spikes right before the vote.
• S&P 500 performance through August – A sustained decline toward the 18% average drawdown could signal the bottom.
• Post‑election earnings reports (Q4 2026) – Strong corporate results could accelerate the typical +14% rebound.

The 18% average dip and 70% correction odds highlight the recurring influence of political cycles on equity markets, leaving the August timeframe as a key inflection point for investors watching the 2026 midterm year.