The future of Japanese technology giant Olympus is in doubt after the company revealed it hid massive losses on securities investments dating from the 1990s.

The admission sent Olympus’ stock plunging by 29 percent to its lowest mark in 16 years. Observers say the revelations could lead to the 92-year-old company being delisted from the Tokyo Stock Exchange.

Olympus President Shuichi Takayama acknowledged Tuesday the losses were hidden in part through a $2 billion purchase of a British medical equipment maker in 2008. The purchase price included a $687 million advisory fee, which was far above the usual fee paid for such a deal.

Another $773 million in losses was hidden through the purchases of three small Japanese companies between 2006 and 2008. The companies had little to no relation to Olympus’ core business, which involves making cameras and hi-tech surgical equipment.

The deals were first questioned by British-born Michael Woodford, who was fired as Olympus chief executive officer on October 14. Woodford told reporters days after his dismissal the scandal rose to the level of criminal activity.

Takayama said Tuesday’s announcement followed a probe by an independent panel. He blamed the scandal on former chairman and president Tsuyoshi Kikukawa, who resigned last month, as well as executive vice president Hisashi Mori and internal auditor Hideo Yamada.

Mori was dismissed from his post Tuesday, while Yamada has resigned. Takayama says the company may seek criminal charges against the trio.