According to CoinMeta, the U.S. stock market is re-evaluating the sustainability of the artificial intelligence (AI) boom. The Nasdaq Composite Index fell 2.6% on Thursday, recording its largest single-day decline since June. Investors are concerned that the rapidly rising spending in the AI sector is not sustainable, leading to a significant drop in U.S. tech stocks. Meanwhile, the Dow Jones Industrial Average, which is relatively more concentrated with blue-chip stocks, rose by 0.02%. Many major AI concept stocks declined, with Meta ( meta.o ) falling 7% after the company disclosed that it will undertake substantial additional expenses in the future. Despite a significant increase in Meta's revenue, profits still did not meet Wall Street's expectations. Analyst Navilier stated that the market is selling indiscriminately, discarding even the good assets as well. NVIDIA CEO pointed out that AI lacks sufficient capital to support the growth of so-called "new type of cloud service providers," which mainly provide digital infrastructure for large AI cloud computing companies such as Meta and Amazon. The Philadelphia Semiconductor Index plummeted by 6.7%. Given the ongoing turmoil in the AI sector this week, U.S. investors are turning to the bond market for safety, avoiding higher-risk assets like tech stocks. As funds flow into the bond market, U.S. Treasury yields have dropped significantly.