Last week, concerns were raised about the U.S. stock market forming a large rounded top, indicating a potential risk of accelerated adjustment. According to Ming Pao, last Friday marked the expiration of numerous derivatives, known as the quadruple witching day, which coincided with the end of the quarter. Throughout the week, options dealers exerted significant effort to keep the three major U.S. stock indices stable. However, by Friday evening, as options settled, the indices broke through several technical support levels, revealing underlying vulnerabilities.