Alibaba, the Chinese e-commerce giant that Ma co-founded, saw its Hong Kong-listed shares drop as much as 9.4% on Tuesday after Chinese state media reported that an individual named “Ma” in Hangzhou – where Alibaba is headquartered – They were arrested on national security grounds. 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...