The U.S. stock market’s current bull run is approaching its fourth anniversary with the S&P 500 up roughly 117% from its October 2022 closing low.
The rally has been powered by strong corporate profits, resilient economic growth and a surge in investment tied to artificial intelligence.
AI concentration is both strength and risk
The largest technology companies now account for an unusually large share of the index, increasing the market’s sensitivity to any disappointment in AI spending or earnings.
Higher Treasury yields and the Federal Reserve’s renewed tightening cycle also pose risks to equity valuations.
Still, the bull market remains one of the strongest postwar advances as investors head into another major earnings season.
Sources
- S&P 500 market data
- Reuters, Oct. 9, 2026
