Former RBS trader Tan Chi Min claims hedge fund asked UK bank to change Libor Mr Tan is claiming $1.5m (£943,000) in bonuses and 3.3m RBS shares that he says the bank owes him in pay. He claims in his lawsuit that asking for changes in Libor was "common practice" among RBS traders and that the bank "took requests from clients" to alter the rate. Regulators across the world are investigating whether banks manipulated Libor during the financial crisis. All of the UK's major banks have issued statements saying they are involved in the investigation, including Barclays, HSBC, Lloyds Banking Group and RBS. Libor is used to price about $360 trillion (£225 trillion) of financial products around the world, including everything from small business loans to complex financial derivatives. The rate is set from a daily survey of leading banks, which are each asked to submit their borrowing rate every morning. The survey is undertaken on behalf of the British Bankers' Association, which represents the interests of the UK banking industry. In the US, federal investigators are involved in the probe, which could potentially lead to criminal charges being brought against those involved if evidence of wrongdoing is uncovered. Swiss banking group UBS has already sought to turn whistleblower and apply for immunity from prosecution in Canada. Court papers filed in the Ontario Superior Court were last month reported to show that UBS was attempting to negotiate a plea bargain-type deal. Traders at several banks have been suspended as the investigation continues, but no formal charges have been brought against any bank employee for manipulating Libor.