In a statement on Saturday, Toshiba said it had no information to disclose now, citing the ongoing investigation.
Shares of Toshiba, whose businesses range from laptop computers to nuclear power plants, fell to as low as 402.0 yen in early trade, or down 22 percent since the company disclosed the internal investigation in early April. The Nikkei average was down 1.3 percent.
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Toshiba has not been able to close its books for the year that ended in March due to the probe. It has also skipped its year-end dividend to
The investigation had previously found inappropriate bookkeeping in areas such as highway electronic toll collection systems, power meters and semiconductors likely led to profits being overstated by nearly 55 billion yen in recent years.
The company has said irregularities found so far included not booking appropriate losses and expenses, as well as underestimating material costs.
The investigation is expected to conclude in mid-July.
The accounting probe is Toshiba's second in less then two years. In October 2013, it announced that it found its medical subsidiary, Toshiba Medical information Systems, had overstated results for several years.