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.

The U.S. Consumer Financial Protection Bureau is suing Capital One, claiming the company cheated customers out of $2 billion by misleading them.

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