(Adds details, background) MOSCOW, Aug 3 (Reuters) - Russia’s central bank has started preparations for the sale of Otkritie bank on the stock market or to a strategic investor, it said on Tuesday, with interested parties requested to apply between Oct. 11 and 22. Otkritie, which was bailed out by the central bank four years ago, is on track for an initial public offering in May 2022, the bank’s president Mikhail Zadornov said in April, with state firms and former owners barred from the sale. On Tuesday, the central bank said the sale could happen this year if there was strong interest in Otkritie, once Russia’s biggest private bank by assets. It also said Otkritie’s insurance and pension businesses could be spun off before the sale if there is such interest from bidders. The sale of Otkritie would mark the end of the central bank’s dual role as both regulator and owner of banks, a position criticed by some in the banking sector. It sold its controlling stake in Russia’s biggest bank Sberbank to the government last year. (Reporting by Elena Fabrichnaya Writing by Katya Golubkova Editing by Mark Potter) Our Standards: The Thomson Reuters Trust Principles.