The loss would deal a yet another heavy blow to a sprawling conglomerate hoping to recover from a $1.3 billion accounting scandal last year.
The Japanese electronics conglomerate said it would make any necessary announcements following a board meeting on the matter on Tuesday.
The potential loss relates to U.S. engineering firm Chicago Bridge & Iron's (CB&I) (N:CBI) nuclear construction business that Westinghouse acquired in December last year for $229 million.
After the deal was completed, CB&I sued Westinghouse over how working capital in the deal should be calculated and which firm would shoulder potential liabilities related to cost overruns at two delayed nuclear power plant projects in the United States.
Toshiba has forecast a full-year net profit of about 145 billion yen this year.
Any big losses are likely to force Toshiba to boost a capital base that has been weakened by range of restructuring steps taken in the wake of the accounting scandal.
As of the end of September, Toshiba had shareholders' equity of 363 billion yen, or just 7.5 percent of assets, which could fall close to zero if the company is forced to log significant losses.