Stocks related to the printed circuit board (PCB) sector in Hong Kong saw a significant plunge during the afternoon trading session. Among them, KB LAMINATES shares plummeted by over 15%, while Kingboard Holdings Limited (note: inferred from context, not in provided symbols) dropped more than 10%. Dingtai High-Tech Co., Ltd. (note: inferred from context, not in provided symbols) also fell by over 7%.