News of his departure was circulated via an internal memo at UBS, which was then leaked to the media.
While Mr Coleman is to stay on at the bank "for the next few months" in an advisory capacity, his chief duties have been handed over to Neal Shear, global head of securities at UBS.
One unnamed executive at the Swiss firm told the Financial Times: "Clearly it is sad that Daniel is leaving but after such a long time it is understandable that he would like to move on."
Last year was a difficult one for the company, in which it cut staff levels by 16 per cent in an attempt to return to profitability.
The job cuts eventually paid off, with UBS reporting a $1.1 billion profit in the final quarter of 2009.
By Gary Cooper