美股三大指数表现分化，医疗保险类股成最大拖油瓶

Group 1 - The U.S. stock market showed mixed performance with the Dow Jones down 0.83% at 49,003.41 points, while the S&P 500 rose 0.41% to 6,978.6 points, and the Nasdaq increased by 0.91% to 23,817.1 points, indicating a divergence in market sentiment [1] - The technology sector, particularly large tech and semiconductor stocks, saw a capital inflow driven by positive news related to AI, while healthcare insurance stocks faced significant selling pressure due to policy and earnings forecast concerns [1][2] - UnitedHealth Group's stock plummeted nearly 20% after it provided a revenue outlook for 2026 that fell short of market expectations, contributing to the decline of the Dow Jones index [2] Group 2 - Micron's stock surged over 5% following the announcement of a $24 billion investment in Singapore over the next decade to meet rapidly growing demand, which is expected to stimulate the related supply chain [2] - SanDisk and Western Digital saw their stock prices rise by over 2% and nearly 5%, respectively, reflecting market optimism regarding the recovery of the storage chip sector and increased demand driven by AI applications [2] - The latest consumer confidence index in the U.S. dropped to its lowest level since 2014, even below pandemic levels, indicating public unease regarding fluctuating tariff policies and trade directions, which adds uncertainty to the market outlook [2]