Japan’s securities watchdog filed criminal charges against a former SMBC Nikko Securities Inc. deputy president, as the trading scandal engulfing the brokerage deepened in Tokyo.

The Securities and Exchange Surveillance Commission asked prosecutors to charge Toshihiro Sato with allegedly manipulating the price of a company’s shares in relation to block offers, it said in a statement Tuesday. The SESC also filed fresh charges against SMBC Nikko and three of the brokerage’s employees, it said.

SMBC Nikko said it sincerely apologizes for causing trouble and concern, and will cooperate with investigations and make efforts to regain trust.