Big U.S. banks have generated about $9 billion annually in revenue from overdrafts, ATMs and other fees in recent years, according to the Center for Responsible Lending, or CRL. The fees have become somewhat of a cash cow for banks over the past 20 years, some experts have said. Taylor Roberson, a fintech regulation expert at CRL, said Bankrate’s survey confirms what researchers have known for years about millennials baring the brunt of banking fees.