Libor (London interbank offered rate), is meant to represent how much banks pay to borrow from one another. It is also a benchmark for at least US$550 trillion worth of contracts spanning interest rate derivatives to residential mortgages. A scandal erupted after banks were found to be rigging the system. Barclays was fined US$453 million by global regulators in June 2012 for manipulating Libor, and UBS was hit with a US$1.5 billion bill in December 2012. In February 2013, RBS was fined US$612 million to settle US and UK regulatory charges of misconduct, manipulation, attempted manipulation and false reporting of yen, Swiss franc and dollar-denominated Libor.