Seven banks—including Bank of America Corp., Barclays Bank Plc, and Citigroup Inc.—agreed to pay $324 million to settle claims they conspired to rig the ISDAfix benchmark, which is used in the sale of interest-rate derivatives and other financial instruments.

The settlements follow a ruling by U.S. District Judge Jesse Furman in Manhattan rejecting the banks' request that he throw out the claims. Furman said in March that a group of investors led by an Alaska pension fund had raised “plausible allegations that a conspiracy among the defendants existed” and allowed the suit to go forward.

The investors claimed that, beginning in 2009, the banks used electronic chat rooms and other means of private communication to set ISDAfix, typically submitting identical rate quotes, investors said in their suit. They were seeking billions of dollars in losses tied to the alleged rate-fixing scheme.