A securities industry watchdog said Tuesday it has filed criminal complaints with prosecutors against Olympus Corp., three of its former executives and three other individuals over their suspected involvement in the company's investment loss coverup.

The six individuals allegedly collaborated in padding the net assets of Olympus by around ¥229 billion in its financial statements for fiscal 2006 and 2007 through such means as shifting securities-related investment losses off its books, the Securities and Exchange Surveillance Commission said in a statement after asking Tokyo prosecutors to indict the camera and medical equipment maker and the six individuals.

The six include former Olympus Chairman Tsuyoshi Kikukawa, 71, and Akio Nakagawa, 61, a former employee of a major Japanese securities house.

If the prosecutors comply with the SESC's request, Olympus could face a fine of up to ¥700 million for each case and the six individuals could each face up to 10 years in prison, according to the commission. The individuals may also face a fine of up to ¥10 million.

Kikukawa, ex-Vice Executive President Hisashi Mori and former auditor Hideo Yamada were arrested on Feb. 16.