A U.S. watchdog is suing Capital One for allegedly misleading consumers about its offerings for high-interest savings accounts — and “cheating” customers out of more than $2 billion in lost interest payments as a result.

Despite its relatively low interest rate, the CFPB alleged, the 360 Savings account was advertised as a high-interest savings account.

Federal regulators said in a lawsuit on Tuesday that the giant bank deliberately underpaid savings account interest, even as rates rose.