(Reuters) -Russia's central bank said on Friday it would study the legality of plans by some banks to impose fees on foreign currency accounts, warning that lenders should not worsen conditions for existing clients.
Some major Russian banks plan to charge fees on retail accounts in dollars and euros after authorities floated the idea of negative interest rates for banks' corporate clients' foreign currency deposits, drawing the ire of customers.
The central bank said it understood banks' concerns over risks in dealing in foreign currencies, but said it would take supervisory measures should lenders be found to have violated contracts with their actions.
Unilateral changes to the terms and conditions of a bank deposit agreement that shorten its term, reduce interest or introduce commissions are a violation of banking laws, the central bank said in a statement.
"Thus, banks may not impose commissions on already opened foreign currency accounts," it said, adding that banks may refuse to offer foreign currency products to customers.
The central bank in late May said the share of foreign currency liabilities Russian banks had has declined recently as clients stepped up withdrawal of funds from their currency accounts, while the share of banks' foreign currency assets has increased.
The bank then said Russia could consider imposing negative interest rates on deposits held in dollars and euros, clarifying that such discussions only concerned corporate clients' foreign exchange deposits with banks, not those of retail clients.
(Reporting by Reuters; editing by David Evans)