Interros holds 30.4% in Power Machines.
"Siemens recently applied to the Federal Anti-Monopoly Service for permission to buy the stake," Interros said.
Power Machines accounts for 37% of the country's turbines, turbo-generators, hydro-generators and electrical equipment market.
The company provides engineering services, and produces, assembles, services and modernizes equipment for hydro, thermal, gas and nuclear power plants and the transportation industry. It has clients in 87 countries.
Power Machines' largest shareholders are Russian electricity giant Unified Energy System and Germany's Siemens, which hold 25% plus one share each, and Interros, the holding company for the world's largest nickel producer Norilsk Nickel, which owns 30.4%.
In July, Interros and UES [RTS: EESR] said they intended to sell their stakes.
The head of UES, Anatoly Chubais, said last month that the deal to sell the UES stake in Power Machines should be completed soon.
In line with an agreement concluded by major Power Machines shareholders, key stakeholders have right of first refusal on buying one another's shares.
