Mike Stewart, a former co-head of equities at Bank of America Merrill Lynch, was hired in July by UBS with the task of co-running its global equities division. He now finds himself in that role – but now as the sole head following the resignations of the Swiss bank’s two global equities chiefs after a $2.3bn unauthorised trading loss in the division last month.

The bank announced yesterday that Yassine Bouhara and Francois Gouws had resigned their posts after a $2.3bn unauthorised trading loss was discovered at the Swiss bank's Delta One trading unit last month.