US authorities have stepped up scrutiny of Chinese groups listed on their shores but remain hamstrung by a lack of access to data and limits to what they can do should they find wrongdoing.
In recent months, short-sellers have descended on a large number of Chinese companies listed on international stock exchanges including New York, Toronto and Hong Kong, accusing them of fraud or other wrongdoing.
The spotlight in the US has fallen on the companies themselves and the promoters, brokers and auditors who help them list shares on stock exchanges through so-called reverse mergers, which allow businesses to bypass the scrutiny of an initial public offering.