The US Federal Deposit Insurance Corporation sued HSBC, Citigroup, Deutsche Bank and 12 other global banking heavyweights for manipulation of the Libor benchmark interest rate.
The regulator said the manipulation caused "substantial losses" to 38 US banks which were shut down due to insolvency during and after the 2008 financial crisis.
The FDIC said the accused institutions cheated the closed banks in US dollar Libor-based swap and other agreements through the manipulation of the rate between 2007 and 2011.
Libor, or the London Interbank Offered Rate, is used as a reference for some USD 350 trillion worth of financial contracts worldwide, from corporate loans to financial swap contracts.
"The Panel Bank Defendants fraudulently and collusively suppressed USD Libor, and they did so to their advantage," the suit said.
The banks named are, or were, participants in setting the daily Libor rate: Bank of America, Citigroup, and JPMorgan Chase of the United States, Germany's Deutsche Bank and WestLB, Britain's HSBC, Barclays and Lloyds banks, Japan's Norinchukin Bank and Bank of Tokyo-Mitsubishi, Credit Suisse and UBS of Switzerland, Royal Bank of Scotland, Royal Bank of Canada, and Rabobank of the Netherlands.
Several of the banks have already paid substantial fines to regulators and justice authorities in the United States and Europe for participating in rate-fixing.
Also sued was the British Bankers' Association, which at the time oversaw the daily fixing of Libor by the banks.
"BBA participated in the alleged scheme to protect the revenue stream it generated from selling Libor licenses and to appease the Panel Bank Defendants that were members of the BBA," it said.
The FDIC said it was seeking full damages for losses incurred by the closed banks, punitive damages, and damages for violating US antitrust statutes.