美股三大指数涨跌不一，英伟达绩后倒跌超2%

Group 1 - Initial jobless claims in the U.S. rose slightly to 212,000 during the Presidents' Day holiday week, but were below expectations [1] - The three major U.S. stock indices showed mixed performance, with the Nasdaq down 0.25%, the S&P 500 down 0.04%, and the Dow Jones up 0.33% [1] Group 2 - Nvidia's stock fell over 2%, despite reporting a record Q4 revenue of $68.1 billion, a 73% year-over-year increase, and providing strong guidance for Q1 [1] - SanDisk's stock rose nearly 3% as it partnered with SK Hynix to initiate the global standardization process for the next-generation memory "HBF" [1] - Synopsys' stock dropped 4.3% after it lowered its earnings per share guidance for fiscal year 2026, leading to target price reductions from multiple major firms [1] - Zoom Video Communications' stock fell over 10% as its Q4 results were mixed, with adjusted earnings per share guidance for the current quarter falling short of expectations [1]