A former Sumitomo Mitsui Trust Bank division manager dismissed for insider trading is suspected of committing the illegal practice at least since he was in a deputy post in 2022, it was learned Thursday.

The Securities and Exchange Surveillance Commission has raided locations related to the former employee on suspicion of violating the financial instruments and exchange law.

The securities industry watchdog is apparently aiming to file a criminal complaint with the Tokyo District Public Prosecutor's Office.

According to informed sources, the former employee in his 50s was in a managerial post at the bank's stock transfer agency division.

The person conducted insider trading while he was in a deputy post in 2022 and continued to do so after being promoted to the managerial post in 2023, the sources said.

The former employee is believed to have traded in several stocks based on tender offers and other information he learned through work and have earned nearly ¥30 million in profits illegally. He admitted the allegations in the SESC's investigations.

The former employee reported the misconduct to the bank in October last year and was dismissed Nov. 1. The bank's parent, Sumitomo Mitsui Trust Group, set up an investigation committee comprising independent outside directors and outside lawyers in November. It is investigating whether there are any similar cases.

The Japanese financial world has been rocked by a series of scandals. A former judge seconded to the Financial Services Agency and a former employee of the Tokyo Stock Exchange have been recently indicted without arrest for their involvement in insider trading in violation of the financial instruments and exchange law.