Canadian Imperial Bank of Commerce has parted company with the head of its investment banking arm and its chief risk officer after a costly and embarrassing foray into US subprime mortgages and other risky securities.

The bank, which has a reputation as the most accident-prone of the big Canadian banks, yesterday named Richard Nesbitt, currently the Toronto stock exchange's chief executive, as head of CIBC World Markets. Mr Nesbitt replaces Brian Shaw, who is leaving after 23 years with the bank.