Zai Lab (09688.HK) experienced a significant downturn in Monday's trading session, with its stock plummeting 5.04% during intraday trading. This sharp decline reflects the broader weakness observed in the Hong Kong biomedical sector.

The fall in Zai Lab's stock price is part of a larger trend affecting biomedical stocks in the Hong Kong market. The sector as a whole faced downward pressure, with several key players seeing substantial declines in their share prices.

Among the affected companies, Junshi Biosciences led the decline with an 8% drop, followed by WuXi AppTec falling 6%. Zai Lab and WuXi Biologics both saw 5% decreases, while Tigermed experienced a 4% decline. This widespread downturn suggests broader market factors or sector-specific concerns affecting investor sentiment towards biomedical stocks in the region.