On the afternoon of September 18, the A-shares experienced a sharp drop, with the ChiNext Index plummeting more than 3%, and over 4300 stocks falling, led by declines in the financial and non-ferrous metal sectors. The total transaction volume of the Shanghai and Shenzhen stock markets exceeded 3.1 trillion yuan (RMB), significantly higher than the previous trading day’s volume of 758.4 billion yuan. Concurrently, the Hong Kong stock market also witnessed fluctuations with the Hang Seng Index dropping over 2%.
The afternoon of September 18 saw a significant plunge in A-shares, as all three major indexes trended downward. By the close of the market, the Shanghai Composite Index dropped by 1.15% to 3831.66 points, the Shenzhen Component Index fell by 1.06% to 13075.66 points, and the ChiNext Index decreased by 1.64% to 3095.85 points.
Stocks across the board experienced declines, with over 4350 stocks recording losses, and sectors like securities, insurance, banks, liquor, and non-ferrous metals all seeing collective declines.
The trading volume of A-shares surged notably, reaching 3.135 trillion yuan in total for the Shanghai and Shenzhen stock markets, a sharp increase from the previous trading day’s volume of 758.4 billion yuan, marking the third highest volume this year. Among them, stocks like Hanwu Ji, East Fortune, SMIC, Eternal Creative, Sanhua Intelligent Control, and Industrial Fulian all had trading volumes exceeding 20 billion yuan. Main capital saw a net outflow of 128.272 billion yuan, with significant outflows observed in large and medium-sized transactions.
According to data from Wind, in the past, there were four trading days where the transaction volume surpassed 3 trillion yuan, which were on October 8, 2024, August 25, 2025, August 27, 2025, and August 28, 2025, with volumes of 3.47 trillion, 3.17 trillion, 3.2 trillion, and 3 trillion yuan respectively.
Regarding the afternoon plunge in A-shares, the Chinese Fund News analyzed that some abnormal phenomena appeared in the market these past two days. On September 17, many securities stocks were suppressed by large sell orders, and a similar situation occurred on the 18th. Some investors noted that stocks like CITIC Securities began to exhibit an “ECG reading” when their prices dropped by about 1% intraday.
The performance of A-shares once again became a hot topic on Weibo.
Financial blogger “Yihao Shenzhen Brother” remarked, “Today in A-shares, we were enjoying hotpot and singing in the morning, but in the afternoon, we went straight from the KTV to the ICU, only an hour apart…”
Blogger “Xiao Qiao’s Insight Analysis” analyzed that the sharp decline at the close revealed two points of information. Firstly, from August till now, the market struggled to break through the 3900-point level several times, indicating a lack of confidence in the market’s ability to surpass and hold above this key level. There is still significant disagreement within the market, leading to prolonged volatility.
Secondly, there were diverging movements between large and small cap stocks throughout the day. Small-cap stocks had a 1% increase, whereas at the close, large-cap stocks fell by 1.2% and small-cap stocks by 1%. This signifies a significant selling pressure towards the end of the session, suggesting that the market has entered a phase of rapid and widespread declines.
Meanwhile, in the Hong Kong stock market, there was a similar afternoon decline, with the Heng Seng Index and Heng Index both experiencing a sharp drop, falling over 2%. Towards the end of the session, the losses narrowed slightly, with tech and internet stocks mostly decreasing, except for outliers like Baidu and Meituan which saw gains. By the market close, the Heng Seng Index fell by 1.35% and the Heng Index dropped by 0.99%.