美股全线下挫，英伟达市值蒸发超1万亿元，黄金重回3500美元

Market Overview - US stock market experienced a broad decline, with the Dow Jones Industrial Average falling by 0.20% to 45,544.88 points, the Nasdaq Composite down 1.15% to 21,455.55 points, and the S&P 500 decreasing by 0.64% to 6,460.26 points [1][2]. Semiconductor Sector - The semiconductor sector in the US saw a significant drop, with the Philadelphia Semiconductor Index plummeting over 3%. Major companies like Nvidia, Broadcom, TSMC ADR, AMD, and Oracle all experienced declines exceeding 3%, while Micron Technology, Applied Materials, ASML ADR, and Intel fell over 2% [3][4]. - Nvidia's market value decreased by $145.6 billion (approximately 1038.2 billion RMB) in one night, with its stock price dropping by 3.3% [4]. AI Chip Companies - Marvell Technology, a US AI custom chip giant, faced severe selling pressure, with its stock price plunging nearly 19% during intraday trading and closing down 18.6% at $62.87, marking a three-month low. The company's market capitalization shrank to $54.2 billion (approximately 38.64 billion RMB) [4]. Chinese Tech Stocks - The Nasdaq Golden Dragon China Index rose by 1.5%, with Alibaba surging 12.9%, marking its largest increase since March 2023. The company has reportedly invested over 100 billion RMB in AI infrastructure and product development over the past four quarters [7][8]. - Other Chinese tech stocks like Baidu and JD.com also saw gains, while Netease and Pinduoduo experienced declines [8]. Gold and Commodities - Gold prices increased due to heightened risk aversion, with COMEX gold futures rising by 1.2% to $3,516.1 per ounce, accumulating a weekly increase of 2.86% and a monthly rise of 5.2% [10][11]. - Silver futures also saw a rise of 2.64%, closing at $40.75 per ounce, with similar weekly and monthly gains [11]. Economic Indicators - The US Personal Consumption Expenditures (PCE) price index for July showed a year-on-year increase of 2.6%, with the core PCE price index accelerating to a 2.9% growth. Consumer confidence has declined, and the trade deficit has widened, leading to a projected slowdown in Q3 GDP growth to 2.2% [13]. - Market expectations for a rate cut by the Federal Reserve in September have risen, with probabilities exceeding 80% [14].