突然，“入通”股频频巨震，发生了什么？

Core Viewpoint - The recent inclusion of multiple Hong Kong stocks into the Stock Connect program has led to significant price volatility and increased trading volumes, presenting both investment opportunities and risks for investors [1][2][4]. Group 1: Stock Performance - Several stocks, such as Yaojie Ankang-B and Baize Medical, experienced extreme price fluctuations after being included in the Stock Connect, with Yaojie Ankang-B surging by 20.13% on September 8, followed by a dramatic drop of 53.73% on September 16 [2][7]. - Baize Medical saw its stock price increase by over 50% on September 15, with trading volatility reaching 85.55% on September 16, before experiencing consecutive declines [2][3]. Group 2: Trading Volume - The average daily trading volume of stocks like Yaojie Ankang-B and Baize Medical surged significantly after their inclusion in the Stock Connect, with increases ranging from several times to dozens of times compared to pre-inclusion levels [3]. Group 3: Reasons for Volatility - The volatility in stock prices is attributed to several factors, including adjustments in index constituents leading to passive buying by related ETFs, increased buying from mainland investors, and speculative trading driven by the innovative nature of the included stocks [4][5][6]. - The adjustment of index constituents has resulted in new stocks being added to the Stock Connect, which has led to substantial buying pressure from ETFs tracking these indices [4]. - The influx of mainland capital has provided additional liquidity, further driving up stock prices [5]. - Speculative trading is also a factor, particularly for stocks in the pharmaceutical sector that have recently gained attention for their innovative products [6]. Group 4: Market Dynamics - Many of the stocks included in the Stock Connect are relatively new, with limited shares available for trading, making them more susceptible to extreme price movements when capital flows in [6]. - The fundamental uncertainties surrounding these companies, such as Yaojie Ankang-B's reported net loss of 123 million yuan in the first half of 2025, highlight the risks associated with investing in these volatile stocks [7].