Capital One is being sued by the US government’s consumer watchdog agency for “cheating millions of consumers” and not paying more than $2 billion in interest to holders of its high-interest savings accounts.

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.