A number of major banks are facing at least two criminal probes in the United States over a major interest-rate fixing scandal that has already led to fines against the banking giant Barclays. Last month, Barclays was fined $453 million by U.S. and British authorities for manipulating the London Interbank Offered Rate, or Libor, which provides the basis for rates on trillions of dollars in transactions across the globe. The manipulation meant millions of borrowers paid the wrong amount on their loans. The Justice Department has now confirmed its criminal division is putting together cases against several large firms and their staffers for taking part in the rate fixing. Meanwhile, the attorneys general of New York and Connecticut have announced they have been conducting a probe of the rate manipulation for the past six months. All told, a slew of civil and criminal cases could cost the financial sector tens of billions of dollars.