An independent investigation unveiled that toshiba overstated its operating profit by 151.8 billion yen ($1.22 billion) over several years in accounting irregularities involving top management. The scandal could lead to the restatement of earnings, a board overhaul and potentially hefty fines at the Japanese conglomerate.

Toshiba President and Chief Executive Hisao Tanaka and his predecessor, Vice Chairman Norio Sasaki, were aware of the overstatement of profits and delay in reporting losses in a corporate culture that "avoided going against superiors' wishes," the investigating committee said.

The overstatement was roughly triple Toshiba's initial estimate. The report said Tanaka and Sasaki had set operating profit targets that the heads of divisions were required to meet, applying pressure by hinting at withdrawing from areas that underperformed.

Toshiba says that it takes the situation very seriously, apologuzed to its shareholders, investors and all other stakeholders and plans to thoroughly analyze and examine the investigation results and recommendations. The company is due to hold a news conference at 5 p.m. (0800 GMT) on Tuesday, shortly before the investigating committee is to hold a separate news conference at 7 p.m. (1000 GMT).