Sony, which makes the VAIO PC, has forecast an operating loss of Y260bn for the financial year ending in March.
The forecast is much worse than analyst predictions of a Y100bn loss, which caused the Sony share price to tumble 8% on the Tokyo Stock Exchange in mid-January.
Sony's shares fell 2.56% during Thursday trading, but the operating loss forecast came too late for investors to react.
The company has blamed the losses on the global economic downturn and the strong Japanese currency, according to the Financial Times.
The Japanese electronics group forecast a Y200bn profit last October, but slashed its sales forecast by 14% after a poor year-end trading period.
Since then the yen has strengthened from 100 to 89 to the dollar. This has put all Japanese electronics makers under pressure by making exports more expensive than those from Korea and Taiwan.
Further losses are expected to come from Sony's restructuring and factory closure plans, which were announced in December, as well as write-offs of inventory that cannot be sold.
Sony has yet to confirm how many jobs will be lost in the restructuring process, but up to 16,000 jobs worldwide could be at risk, including 2,000 in Japan.
Further details of Sony's restructuring plans are expected to be made by chief executive Howard Stringer later today.