UBS stands to lose out on potentially tens of millions of pounds in fees after missing out on a slot as either an adviser or underwriter to Prudential, one of its longest-standing clients, on both a major acquisition and a £14bn (€15.4bn) rights issue.

The UK insurer is poised to acquire AIG's Asian assets for $35.5bn (€26.1bn) and launch a corresponding £13.9bn rights issue to help finance the deal, according to a statement today.