美股三大指数小幅高开，微软总市值重新站上4万亿美元

Group 1 - The U.S. stock market opened slightly higher on October 28, with the Dow Jones index rising by 0.65%, the S&P 500 index increasing by 0.31%, and the Nasdaq Composite index up by 0.54%, all reaching new historical highs [1] - Microsoft shares rose over 3%, with the company's market capitalization surpassing $4 trillion, following OpenAI's agreement to purchase an additional $250 billion worth of Microsoft Azure services [1] - United Parcel Service (UPS) opened with a 12% increase, as the company raised its full-year earnings outlook for 2025 to at least $14.90 per share, with adjusted earnings per share projected to be at least $16.25 [1]