S&P 500 Bull Market Marks Four Years as AI Rally Drives 117% Gain Since October 2022

The S&P 500 bull market turned four years old on October 12, 2026, having begun on that same date in 2022. Since its inception, the index has surged approximately 117%, fueled in large part by relentless enthusiasm around artificial intelligence and the spending commitments of major technology companies.

The rally has added trillions of dollars in market value, with the S&P 500 near record highs and volatility subdued heading into the anniversary. Corporate profits have remained rock-solid throughout, providing a fundamental backdrop that has helped sustain investor confidence even as the index climbed into historically elevated territory.

The gains are heavily concentrated, however. A Reuters analysis published on the anniversary found that more than 4 in 10 S&P 500 stocks are lower in 2026 year to date, even as the benchmark index is up roughly 14% on the year. Goldman Sachs data has shown that stripping out AI-related names leaves a version of the index that has gone essentially nowhere since February, underscoring how a handful of chipmakers and AI platform companies are driving nearly all the headline returns.

Analysts debating what could end the run point to no single clear threat, though questions around the breadth of participation, lingering inflation, and the durability of AI capital expenditure cycles remain active concerns. The S&P 500 hit its first record close since August on October 6, just days before the anniversary, extending a four-session winning streak on the back of AI optimism and a pullback in oil prices.