A second banker at the centre of the controversy over Citigroup's multi-billion euro government bond trades last year has left the bank, four months after returning from a leave of absence.

Christopher Sayers, one of seven bankers named by Italian prosecutors in July as part of their criminal investigation into the €15bn ($17.6bn) trades on the EuroMTS platform, left the US bank on October 28, according to filings at the Financial Services Authority, the UK regulator.