Limiting bank overdraft fees may cost the industry more than $15 billion in revenue and prompt lenders to impose new charges to close the gap, the head of Oliver Wyman's North American financial services business says.

"To take that out of the banking system, then that's $15 billion of capital that is not being created," Michael Poulos of the Marsh & McLennan Cos. unit said in an interview this week. "For some of our clients, this is a very big deal, and it's not clear that regulators have thought everything through."

The Federal Reserve said this month that it would ban overdraft fees on automated teller machines or debit cards, unless a customer has agreed to pay extra charges for exceeding account balances. The crackdown came after criticism by lawmakers and consumer groups that bankers drove up fees by misleading consumers on the terms of credit and debit cards.

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