暴涨又闪崩，又一“妖股”诞生

Group 1 - The article discusses the dramatic fluctuations in the stock price of Yaojie Ankang, a biotech company that went public less than three months ago, highlighting a peak market capitalization of nearly 270 billion HKD followed by a significant drop [1][2] - Yaojie Ankang's core product, Tinengotinib, is a multi-target kinase inhibitor aimed at treating various resistant and recurrent tumors, but the company has no revenue and high R&D costs typical of clinical-stage biotech firms [4][5] - The stock's volatility was exacerbated by its small float and the lack of short-selling options in the Hong Kong market, leading to extreme price movements driven by speculative trading [5][16] Group 2 - The turning point for Yaojie Ankang occurred on August 25 when it was announced that the company would be included in the Hang Seng Index series, which created a surge in demand from index-tracking funds [7][9] - Following its inclusion in the index, Yaojie Ankang's stock price skyrocketed, with daily increases of 77.09% and 115.58% on September 12 and 15, respectively [7][10] - The sudden demand for the stock, which previously had low trading volumes, led to a supply-demand imbalance, causing extreme price volatility [14] Group 3 - After the initial surge, the stock price plummeted as investors realized the stock was overvalued, leading to panic selling among retail investors who had bought in at high prices [15] - The incident highlights flaws in the index inclusion mechanism, where the focus on innovative drug labels may overlook liquidity and market stability, contributing to the stock's volatility [17][21] - The lack of timely information disclosure regarding the index changes further complicated the situation, making it difficult for ordinary investors to react appropriately [22][23]