On May 21, U.S. major stock index futures are currently pointing to a lower open on Thursday, as U.S. stocks may give back some of their gains following the rebound in the previous trading day. The rebound in U.S. stocks yesterday coincided with a sharp decline in both U.S. Treasury yields and oil prices. Additionally, Nvidia's stock price fell in pre-market trading, and the market's negative reaction to Nvidia's earnings report may also weigh on U.S. stocks today. Dan Coatsworth, market director at AJ Bell, stated that the chip giant Nvidia is increasingly resembling a 'broken record,' repeatedly playing the same message. It merely states that AI demand is strong, with a large number of customers waiting to buy its chips, and that there is still significant room for growth in the future. The market's current focus is on how long Nvidia can maintain this momentum; even the fastest and strongest athletes can experience exhaustion, and investors are beginning to worry that Nvidia may not be able to sustain its current growth rate.