While Russian banks' exposure to Ukraine was significant, it remained manageable, said Sovgyra. Credit losses could be "easily absorbed from the current year's earnings," he said. Sovgyra said that of the exposure, the $4 billion to $5 billion secured by natural gas was probably the least risky. Assets of subsidiaries might become impaired as the loan books of Ukrainian banks started showing more non-performing assets, he added. He could not estimate how much of the $20 billion to $30 billion might be written off or deemed nonperforming. German Gref, chief executive of Russia's largest bank Sberbank, said in December it would be able to absorb losses there thanks to its strong capital base. Sberbank had exposure of 130 billion rubles ($4 billion) to Ukraine — or less than 1 percent of its balance sheet of $460 billion — at the end of the third quarter. VTB said in December it had made adequate provisions against its risks in Ukraine.