On Thursday, the Shanghai Composite Index declined by 0.2% to fall below the 4,120 mark, while the Shenzhen Component dipped by 0.3% to reach 14,200, extending the decline from the previous trading session. This downturn was prompted by the imposition of stricter margin requirements that have tempered the recent upward momentum in the markets. On Wednesday, in an effort to mitigate excessive risk within the capital markets, Chinese authorities increased the minimum margin requirement for stock financing from 80% to 100%. Concurrently, U.S. President Donald Trump authorized the sale of Nvidia's H200 AI chips to China, with the United States expected to receive 25% of the proceeds. However, there are emerging reports that Chinese customs may potentially block these chip imports. Losses were primarily led by technology and defense sectors, with notable declines in companies such as Leo Group (-3.1%), BlueFocus Intelligent (-11.7%), Zhongji Innolight (-1.1%), and China Spacesat (-9.5%).