突发！跳水！

Group 1: A-Share Market Performance - A-shares experienced a strong rally on October 21, with the Shanghai Composite Index surpassing 3900 points and the ChiNext Index rising over 3% [3] - The Shanghai Composite Index increased by 1.36%, the Shenzhen Component Index rose by 2.06%, and the ChiNext Index gained 3.02% [3] - A total of 4628 stocks rose, with 92 hitting the daily limit up, while 729 stocks declined [4][5] Group 2: Sector Performance - The deep earth technology sector saw a collective surge, with stocks like Zhengyuan Dixin and Sinochem Geotechnics hitting the daily limit up [6] - CPO and other computing hardware stocks continued to strengthen, with Hui Lv Ecology hitting the daily limit up and Xin Yisheng rising over 10% [7] - The consumer electronics sector also saw gains, with companies like Yunzhu Technology and Huanxu Electronics hitting the daily limit up [8] Group 3: Japanese Stock Market Dynamics - The Japanese stock market experienced significant volatility, with the Nikkei 225 index initially rising but later dropping, reflecting profit-taking by investors [10][14] - The Nikkei 225 index had previously surged nearly 15% over the past month, outperforming the S&P 500 index [14] - Analysts predict the Nikkei 225 index could rise to 52000 points by the end of the year, driven by expectations of U.S. interest rate cuts and excess liquidity [16] Group 4: Commodity Market Reaction - International precious metal prices plummeted, with spot gold falling below the 4300 USD mark, experiencing a daily decline of 1.3%, while silver dropped nearly 3% [16][17]