Alibaba, the Chinese e-commerce giant Ma co-founded, saw its Hong Kong-listed shares drop 9.4% on Tuesday after Chinese state media reported that an individual named “Ma” in Hangzhou – where Alibaba is headquartered – had been arrested. For reasons of national security. According to China’s state broadcaster CCTV, the suspect was placed under “compulsory measures” on April 25 on suspicion of “collusion with hostile anti-China forces abroad” for “inciting separatism” and “inciting the undermining of state power.” The one-sentence report, which was quickly picked up by other state media and alerted across Chinese news platforms, sparked panic selling in Hong...