Toshiba overstated its profits by 151.8bn yen ($0.8bn) over several years with the knowledge of senior executives.
That's the findings of an independent review of goings on at the firm which was launched in April to identify irregularities in its accounting and is around three times the figure which had been expected.
It's likely the company will now have to restate its profits and the scandal may spur a management overhaul. Stretching back to 2008, the period covers the tenure of Chief executive Hisao Tanaka and former chief, now chairman, Norio Sasaki.
Toshiba could also face the ire of regulators in Japan
The company said it took the situation very seriously, apologising to shareholders and investors. Shares in the business have fallen by as much as 22 per cent since the irregularities were first discovered.
The company will release the full report tomorrow, followed by a press conference.