The lawsuit claims the banks "have been able to extract billions of dollars in monopoly rents, year after year, from the class members in this case."

According to a report by Reuters:

The class action lawsuit, filed in U.S. District Court in Manhattan, accuses Goldman Sachs Group (GS.N), Bank of America Merrill Lynch (BAC.N), JPMorgan Chase(JPM.N), Citigroup(C.N), Credit Suisse Group (CSGN.VX), Barclays Plc (BARC.L), BNP Paribas SA (BNPP.PA), UBS (UBSG.VX), Deutsche Bank AG (DBKGn.DE), and the Royal Bank of Scotland (RBS.L) of colluding to prevent the trading of interest rate swaps on electronic exchanges, like the ones on which stocks are traded.

As a result, the lawsuit alleges, banks have successfully prevented new competition from non-banks in the lucrative market for dealing interest rate swaps, the world's most commonly traded derivative.