Shares in Commerce Bancorp plunged more than 8 per cent to $31.83 yesterday after the bank disclosed that federal regulators have launched a probe into certain transactions with corporate insiders.

Commerce, a regional bank in New York, New Jersey and Pennsylvania, said the Office of the Comptroller of the Currency and the Federal Reserve are investigating transactions between the bank and its officers, directors and related parties, including transactions invol-ving bank premises.