The Securities and Exchange Surveillance Commission (SESC) conducted an investigation at the headquarters of MUFG Bank, one of Japan's megabanks, over an employee's alleged involvement in insider trading.

The employee allegedly provided a family member with information about a client's prospective tender offer before the bid became public. The relative then used this information to trade stocks and netted several million yen in profits.

The SESC suspects that the employee divulged information about the prospective takeover bid on multiple occasions. The stock prices of the companies involved rose after the takeover plan was announced.

The employee denied disclosing the information to benefit their relative. The SESC also investigated Mitsubishi UFJ Morgan Stanley Securities Co., where the employee worked on a temporary assignment from the bank.

This investigation follows a recent order from the Financial Services Agency for MUFG Bank, Mitsubishi UFJ Morgan Stanley Securities Co., and another securities firm to improve their operations after they were found to have shared undisclosed information about customer businesses without permission.

Insider trading is prohibited under Japan's Financial Instruments and Exchange Act. The law also forbids individuals with access to nonpublic information from recommending stocks to others based on that information.