Shengu Group (601091.SS) fell 34.71% to 37.72 yuan on September 21, just three trading days after listing on the Shanghai Stock Exchange main board. The stock opened down 48.07%, triggered two intraday halts and ended with a market capitalization of about 117.3 billion yuan ($17.6 billion). That followed gains of 373.81% on its first day and 177.74% on the second, when it reached an intraday peak of 82.59 yuan, nearly 18 times its 4.39-yuan IPO price. Its market value briefly reached 250 billion yuan ($37.4 billion). The Shanghai Stock Exchange suspended accounts involved in abnormal trading and said it would continue monitoring the shares. Shengu Group also warned that its valuation had far exceeded industry averages and that a sharp pullback was possible. The stock's 6.79% free float (shares available for public trading), unrestricted first-five-day price movement and low IPO price amplified volatility. Meanwhile, the company's 2026 outlook points to slower revenue growth and falling net profit, while overdue receivables represented 61.41% of total accounts receivable at the end of 2025. Whether the rally can persist or the market capitalization above 100 billion yuan can be sustained remains highly uncertain.