Private equity chief Marc Rowan warns that America’s retirement system is overly reliant on Nvidia’s performance, with the chipmaker’s $5tn market cap dwarfing other stocks. A recent UBS analysis reveals just 42 stocks drive the S&P 500’s returns, down from the usual 100, as AI-driven tech blue-chips like Alphabet, Microsoft, and Apple dominate. The equal-weighted S&P 500 lags behind, highlighting growing market concentration.

Meanwhile, non-AI sectors face turmoil: Shake Shack reported negative like-for-like revenue in April due to weak tourism, Planet Fitness missed growth targets amid consumer debt concerns, and Whirlpool saw a 10% drop in appliance demand, suspending its dividend. These declines, though smaller in scale than Nvidia, signal a widening gap between AI winners and traditional industries. While the S&P’s top-heavy structure shields investors from broader cracks, overreliance on AI stocks risks exposing portfolios to volatility if expectations shift.