Shengu Group (601091.SS) fell 34.71% to 37.72 yuan on September 21, only three trading days after listing on the Shanghai Stock Exchange main board. The shares had surged 373.81% on the first day and 177.74% on the second, reaching 82.59 yuan, nearly 18 times the 4.39-yuan IPO price, before the September 21 selloff reduced market capitalization to about 117.3 billion yuan ($17.6 billion). The stock triggered six intraday trading halts across its first three sessions, including two on September 21. The Shanghai Stock Exchange suspended accounts involved in abnormal trading, reported 50 abnormal-trading cases between September 14 and September 18, and said it would continue monitoring Shengu Group. The company warned that its valuation ratios were far above industry averages and that a sharp pullback was possible. A 6.79% free float, unrestricted first-five-day price movement and low IPO price amplified volatility, while Shengu's 2026 outlook indicated slower revenue growth and falling net profit. Overdue receivables represented 61.41% of total accounts receivable at the end of 2025, adding to concerns about the durability of the rally.