UBS’ investment bank is an "accident waiting to happen", which is holding back its world class wealth management business, says activist investor Knight Vinke.

The Swiss bank must be wondering what else it has to do to get people off its back. Just a few weeks after a maiden set of quarterly results for the slimmed-down UBS Investment Bank, which seemed to suggest it was getting back on its feet after a radical restructuring last year, UBS faced a demand from activist investor Knight Vinke to go even further.