UBS, the world's largest wealth manager, is facing embarrassment over fresh revelations going back to the tax investigation that led to the collapse of Swiss banking secrecy. Two significant events are looming before UBS. The first is the possibility of a public trial in France, featuring UBS whistleblower Bradley Birkenfeld, concerning historic tax evasion allegedly orchestrated by the bank. The other is the publication ... of Birkenfeld's scathing new book, Lucifer's Banker, which covers his time at UBS. The tax evasion controversy, which was first highlighted in 2005, subsequently involved the US Department of Justice, the State Department and Internal Revenue Service. It was prompted by disclosures made by Birkenfeld that UBS had helped wealthy US citizens evade taxes. In 2009, UBS paid $780m (588m, 693m) to US authorities to avoid prosecution. Birkenfeld served 31 months in prison for one count of conspiracy to abet tax evasion by one of his clients. After he was released he was paid a record $104m by the IRS for helping recover unpaid taxes. However, Birkenfeld has since said that he was systematically prevented from giving testimony in open court - but this may be about to change thanks to the French authorities. Birkenfeld claims the UBS coverup stretches to the highest levels of the US establishment. He promises four big names will be exposed in his book, [and] claims there was a glaring conflict of interest involving then Senator Barack Obama, which essentially placed him on the UBS payroll.