The Consumer Financial Protection Bureau is suing Capital One, which it says kept customers in the dark about higher-yielding savings accounts.

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.