As 2009 winds down, big banks around the globe are sorting out one last headache: whether to spread the pain of the UK's new bonus tax among their global work forces by cutting bonus pools all over the world.

The banking sector was roiled this month when the UK said it would impose a new 50% tax on the portion of discretionary bonuses above £25,000 ($40,355). While the tax is to be paid by employers, it threatens to dent employees' bottom line by encouraging banks to pay smaller bonuses as the industry emerges from the financial crisis, which was the goal of the UK Government in imposing the tax.