Text size Alibaba stock and other Chinese tech shares were tumbling on Monday as amid fresh fines from market regulators over disclosure rules. China’s State Administration for Market Regulation announced Sunday a wave of penalties for improperly reporting past deals, in breach of competition law. Alibaba (ticker: BABA) and Tencent (0700.H.K.) were among the companies fined as a result. Shares in e-commerce powerhouse Alibaba tumbled 8.6% in the U.S. premarket, with internet giant Tencent ’s stock trading 3% lower in Hong Kong. The selloff was felt across the sector, dragging down other Chinese tech stocks including JD.com (JD) and NetEase...