To date, rate rigging has resulted in billions of dollars of regulatory fines being handed out to banks worldwide.

Citigroup, Deutsche Bank and HSBC have agreed to pay a combined $132 million fine to settle a US lawsuit filed by future traders who accused them of rigging Libor, the inter-bank lending benchmark rate.

Citigroup, Deutsche Bank and HSBC will pay $33.4 million, $80 million and $18.5 million, respectively. The money would go to proposed classes comprising of anyone who traded in Eurodollar futures on exchanges, including but not limited to the Chicago Mercantile Exchange, between January 1, 2003 and May 31, 2011, according to a court filing. 

The London Interbank Offered Rate, or Libor, is used by banks to set rates on credit card, mortgage, student loans and other transactions, and to determine the cost of borrowing from each other. Recent scandals about how the rate was rigged, leading to fines and punishments for a raft of banks, have led to the UK's financial regulator to call for an overhaul. A new way of setting such a rate could take shape as soon as 2021. There have been calls for alternatives to the LIBOR system, with the idea of basing interest rates on transactions rather than bankers’ judgements.