There doesn't seem to be any one answer, but instead the plunge in the company's shares appears to owe to a confluence of several factors. Kingsoft's stock plunged 48% in a single trading day in March after the U.S. securities regulator started turning up the volume in its threats to delist Chinese companies from U.S. stock exchanges unless it could gain access to their auditors' work papers. China bans auditors of its companies from handing over those working papers to foreign governments, saying such information is "state secrets."