[Institutions in Hong Kong step up efforts to clean up illegal transactions in the mainland, and many tighten some measures to wait and see] October 1st, the window for mainland investors to participate in cross-border transactions in the Hong Kong capital market through illegal channels has become increasingly closed. The reporter learned that many Chinese securities firms in Hong Kong have tightened their existing mainland business: Mainland investors who log in to their accounts in the mainland can only sell and withdraw money, but cannot deposit and buy. The key to whether it is restricted or not is whether the IP address of mainland investors logging into their Hong Kong securities accounts is displayed in the mainland. (China Business News)