【收盘】A股午后直线下挫，三大股指跌超1%：两市成交31352亿元

Market Overview - The three major A-share indices opened lower on September 18, with significant fluctuations in the semiconductor sector leading to early gains [1] - By the afternoon, all three indices continued to decline, with the ChiNext Index dropping over 2% at one point [1] Sector Performance - The financial sector experienced a broad decline, while the non-ferrous metals industry fell sharply following the Federal Reserve's interest rate cut [1] - Real estate, oil, and media sectors showed weakness, whereas the robotics and semiconductor supply chain saw a pullback after initial gains [1] - The SPD and tourism sectors performed well in the afternoon, showing resilience against the overall market trend [1] Index Closing Figures - The Shanghai Composite Index closed down 1.15% at 3831.66 points [1] - The Sci-Tech Innovation 50 Index increased by 0.72% to 1380.35 points [1] - The Shenzhen Component Index fell by 1.06% to 13075.66 points [1] - The ChiNext Index decreased by 1.64% to 3095.85 points [1] Trading Volume - The total trading volume in the Shanghai and Shenzhen markets reached 31,352 billion yuan, an increase of 7,584 billion yuan compared to the previous trading day [1] - The Shanghai market accounted for 13,660 billion yuan, up 3,593 billion yuan from the previous day, while the Shenzhen market saw a volume of 17,692 billion yuan [1] Stock Movement - A total of 1,026 stocks rose, while 4,348 stocks fell, with 52 stocks remaining flat [1] - There were 80 stocks with gains exceeding 9%, and 6 stocks with losses exceeding 9% [1]