Takafumi Horie, the former boss of Japanese internet firm Livedoor, has been indicted on charges of breaking securities laws, according to reports.
Mr Horie has denied any illegal actions
Together with three other Livedoor executives, Horie has been in custody since 23 January, when he was arrested on suspicion of misleading investors.
The Kyodo news agency said they are accused of spreading false financial information about a takeover in 2004.
They are also accused of inflating the financial figures of a subsidiary firm.
Livedoor's shares have plummeted almost 90% since the investigation began.
Last Friday, the securities watchdog filed a similar criminal complaint against Mr Horie and Livedoor.
Mr Horie, a celebrity in Japan who is known for his critical views of the country's business establishment, has denied any wrongdoing.
Livedoor's problems have shaken the country's business world and stock market and there are fears more problems may emerge.
One of Japan's best known internet companies, it had grown through a series of acquisitions and stock splits.