Russian bank VTB said it would stay for at least three years as an investor in T2 RTK Holding, the countrys No.4 mobile carrier being formed from the merger of Tele2 Russia and the wireless assets of Rostelecom. State-controlled VTB bought Tele2 Russia from Nordic telecoms group Tele2 for $3.6 billion last April. It later agreed to sell half of the business to a group of investors including affiliates of Bank Rossiya and entities of Alexei Mordashov, a billionaire tycoon who controls steelmaker Severstal. And last year, Tele2 Russia, already the countrys No.4 mobile operator, decided to merge with the wireless assets of Rostelecom, aiming to close the gap on MTS, Megafon and Vimpelcom which together control more than 80 percent of the Russian mobile market.