美股高开低走，纳指、标普500指数盘中创历史新高

Group 1: U.S. Stock Market Performance - On July 31, U.S. stock indices collectively declined, with the Nasdaq and S&P 500 reaching intraday all-time highs [1][4] - The Dow Jones index fell by 0.74% to 44,130.98 points, the Nasdaq index decreased by 0.03% to 21,122.45 points, and the S&P 500 index dropped by 0.37% to 6,339.39 points [4] - Major tech stocks showed mixed performance, with the "Big Seven" tech index rising by 1.31% [6] Group 2: Company Earnings Reports - Meta's stock surged by 11.25% following better-than-expected earnings [6][3] - Amazon reported Q2 revenue of $167.7 billion, a 13% year-over-year increase, and net profit of $18.16 billion, up 34.7% year-over-year, but its stock fell over 7% in after-hours trading [7][10] - Apple's Q2 revenue reached $94.036 billion, a 9.63% increase year-over-year, with net profit of $23.434 billion, up 9.26% year-over-year [10] Group 3: Commodity Market Trends - International gold demand reached 1,249 tons in Q2 2025, a 3% year-over-year increase, driven by strong investment demand [15] - Global gold jewelry demand decreased in volume but increased in value during the same period [15] - Oil prices saw a slight decline, with Brent crude down by 0.99% to $71.75 per barrel and WTI crude down by 0.91% to $69.36 per barrel [12][13]