A Bank of America August global fund manager survey found that 32% of investors view an artificial intelligence bubble as the biggest tail risk, meaning a rare but severe event that could hit financial markets hard. Another 27% of respondents said a disorderly rise in bond yields was the second-largest tail risk. At the same time, confidence in U.S. equities outperforming other regional markets strengthened further. The survey showed 27% of fund managers were overweight U.S. stocks relative to global benchmark weights, up 3 percentage points from July and the highest level since December 2024. U.S. equities have still outperformed most overseas markets this year, with the S&P 500 up 13% and the STOXX Europe 600 up 10%, although Japanese and South Korean stocks have done better than the U.S. market over the same period.