When did it become legal to establish private commercial banks in russia?

According to the book Petrostate: Putin, Power and the New Russia by Marshall Goldman, it became legal to establish private commercialized banks in 1987, wherein the capital requirement was of $750,000. The non-spetbanks, which appeared after the announcement of the Law on Cooperation in1988 and registered before 1991, and the new banks which were registered after 1991 all function as private commercialized banks.