The Osaka Securities Exchange on Friday filed a 520 million yen damages suit against two former executives over their involvement in illegal stock trading.
The lawsuit was lodged with the Osaka District Court.
The bourse is seeking compensation from Kyoji Kitamura, former OSE president, and Takuo Noguchi, former OSE vice president.
The latter was indicted in July for allegedly falsifying stock option deals between 1998 and 2000.