美股科技股狂欢，闪迪涨近10%，耐克重挫，热门中概股爆发，中金科工业大涨17%

Market Overview - On December 19, U.S. stock indices opened higher, with significant gains in technology stocks and a surge in popular Chinese concept stocks [1] - The Dow Jones index rose by 281.77 points (+0.59%), the Nasdaq increased by 268.41 points (+1.17%), and the S&P 500 gained 57.68 points (+0.85%) [2] - Major tech companies saw positive movements, with NVIDIA up nearly 3%, while Microsoft, Google, Tesla, and Amazon experienced slight increases [2][3] Chinese Concept Stocks - The Nasdaq Golden Dragon China Index rose over 1%, with notable gains in Chinese companies such as Zhongjin Kexin (+17.41%), Pony.ai (+7.96%), and XPeng Motors (+6.80%) [3][4] - Pinduoduo announced a governance structure adjustment, implementing a co-chairman system and appointing Zhao Jiazhen as co-chairman alongside Chen Lei [3] Nike's Performance - Nike's stock opened significantly lower, dropping nearly 10% to a new low since April, following a report of a 32% year-over-year decline in net profit for Q2 FY2026 [4][5] - Analysts expressed skepticism regarding Nike's performance recovery, as the company anticipates a revenue decline in Q3 [4] Precious Metals and Cryptocurrency - Gold prices slightly decreased, fluctuating around $4,330 per ounce, while silver prices rose above $66 per ounce, gaining over 1% [5] - Bitcoin's price recovered to above $88,000, despite a near 0.2% decline during the day, with over 150,000 individuals liquidated in the crypto market, totaling nearly $500 million [7][8][9] Options Expiration Impact - December 19 marked a "quadruple witching" day, with significant expirations of index options, stock options, index futures, and futures options [9] - Goldman Sachs reported that over $7.1 trillion in nominal options exposure is set to expire, with approximately $5 trillion related to the S&P 500 index [9]