The company may have to mark down its past operating profit by more than ¥100bn ($814m).
Toshiba expects to face ¥300bn to ¥400bn ($2.4bn to $3.2bn) in charges associated to improper accounting regularities, which may also force its chief executive Hisao Tanaka to resign.
The company’s improper book-keeping practices allegedly resulted in an overstatement in profits by over ¥170bn.
Toshiba earlier appointed a third-party committee to probe its past book-keeping practices after finding irregularities. The committee is due to release its report next week.
Citing people familiar with the matter, Reuters reported that the charges include six years of overstated profits uncovered by the committee, and several writedowns.
A Toshiba spokesman told the news agency it has not yet compiled any estimates of possible charges.
The investigation resulted in the suspension of Toshiba’s year-end dividend payout and the company’s accounts for the last financial year have also not been finalised.
There was no clarity on how much of the charges would be booked in 2014. The company posted a net income of ¥51bn in the last fiscal year through March 2014.
Other people with knowledge of the investigation said the committee is looking whether top officials have knowingly encouraged irregularities.
Toshiba is expected to mark down its past operating profit by more than ¥100bn ($814m), almost double its previous estimates, due to accounting irregularities.
The company expects to post the earnings by the end of next month, crossing its original dead line of June.