When Michael Sherwood’s resignation as co-chief executive of Goldman Sachs International was announced to staff at the bank this week, they got more than a memo – they also received a voicemail from the man himself.

In Sherwood's voicemail, left for staff in Europe shortly after a memo on his resignation was sent on November 21, the three-decade Goldman banker told colleagues that it was "with a heavy heart" that he was announcing his retirement.