Daniel Coleman, a 24-year UBS veteran who joined as a graduate trainee and rose to become global head of equities is leaving to “take up a new challenge,” in the industry.

At this stage, it’s not entirely certain what that new challenge will consist of. Nor is it entirely clear why Coleman decided to go. However, rumours and speculation are rife.

On one hand, it’s alleged that Coleman’s exit may have been ‘facilitated’ by Neil Shear, the head of global securities who joined UBS in January after being demoted at Morgan Stanley. Shear will temporarily replace Coleman as head of global equities. Rumour has it that UBS has been looking at alternatives such as Tim Throsby, the former head of Citadel in Asia.

On the other hand, it’s suggested that Coleman chose this moment to quit out of disgruntlement. The Financial Times says he first contemplated leaving 15 months ago when UBS began losing people after the 2008 bonus round.

Are UBS fixed income people getting all the cash?

However, headhunters claim that Coleman may also have been peeved by the fact that after paying its equities staff badly for 2008, UBS didn’t pay them particularly well for 2009 either.

Instead, the Swiss bank is said to be focused on hiring – and paying – in fixed income.

“A lot of the money they made went to fixed income people, and equities feel they lost out,” alleges one London equities headhunter.

Notably, Shear has a fixed income background. In January, UBS also hired Roberto Hoornweg, previously head of global interest rates, credit and currencies at Morgan Stanley, as global head of securities distribution.

It doesn’t help that UBS has performed badly in equities of late. Last week’s report from Mercer Oliver Wyman shows the bank’s share of global equity sales and trading revenues plummeted from 9.8% to 6.4% between the 1st half of 2007 and the 2nd half of 2009. Goldman’s share went from 13.8% to 19.1% over the same period.

Another London equities headhunter predicts further senior departures from the UBS equities bench very soon. “They’ve deferred 60% of comp and they’ve clawed back some of the pay from last year. The feeling there is they’ve hired these fixed income people from Morgan Stanley and they’re in charge.”

UBS declined to comment.