The Diet passed a bill Wednesday to ease curbs on banks' investments in nonbanking firms, punish leaks of corporate information used for insider trading and toughen penalties on investment managers using false information to win contracts.

The portion of the bill revising the banking law relaxes the rule that limited banks in principle to only being able to hold 5 percent stakes in nonbank companies.

The revision allows banks to hold 100 percent stakes in liquidated companies for up to three years and in small and medium-size firms for up to five years.