A Goldman Sachs executive who goes by the nickname "Chunky but Funky", is under investigation in the US for aiding insider trading by the bank's hedge fund clients.
The FBI is examining whether David Loeb, a Goldman managing director, passed illegal tips about technology company stocks to hedge fund traders.
Mr Loeb's role at the bank is managing relationships with important hedge fund clients, with the aim of encouraging them to trade through Goldman Sachs.
A technical sector specialist who speaks Chinese, he has cultivated a reputation as a colourful character within the bank.
He often signs off emails as "cbf", which stands for "Chunky but Funky".
Goldman declined to comment yesterday on the investigation, which was first reported in The Wall Street Journal.