According to CoinMeta, the S&P 500 index has risen by 117% since October 2022, but its top 10 companies currently account for about 40% of the market value, raising concerns about the concentration of artificial intelligence. The index is set to celebrate its fourth anniversary on October 12th and is still close to its historical high, making it the sixth strongest bull market in the United States since World War II. Despite rising oil prices and treasury yields exceeding 5%, the S&P 500 has risen by more than 13% in 2026. Companies related to artificial intelligence have played a central role in this round of growth. NVIDIA has benefited from the demand for AI accelerators, while Microsoft, Google, Amazon, and Meta continue to make substantial investments in data centers and computing infrastructure. According to S&P P Dow Jones Indices data, at the end of August, the market value of the top 10 companies accounted for 37.8%, and by September 25th, this proportion had risen to about 40.4%.