Pedestrians walk past a logo of Toshiba Corp outside an electronics retailer in Tokyo, Japan. Reuters

Shares in Japan’s Toshiba Corp extended losses on Friday, weighed down by concern over a potentially bigger-than-expected US$6 billion writedown triggered by cost overruns at its US nuclear business.

The shares fell as much as 6% in early trade before reversing and have lost almost half their value since December when the company first warned of the problems at the US unit.

Separately, Toshiba is reportedly in talks with the Development Bank of Japan and other lenders for financial aid, though this will involve the company selling off some other businesses, such as its flash memory operations.

That business could be worth several billion dollars and investment funds such as Permira and Bain Capital have expressed interest, Kyodo news agency reported. A Toshiba spokesman said the company is considering a spinoff of its memory chip business and a partial stake sale, but didn’t give specifics.

Toshiba is expected to sell 20 to 30 percent of the chip business, Kyodo reported, citing unidentified sources. Industry sources have said Toshiba’s chip business could be valued at more than 1 trillion yen (US$8.7 billion), although some estimates for the unit have ranged as high as 2 trillion yen.

A source familiar with matter said this week that potential buyers include business partner Western Digital Corp.  The California-based data storage company operates a Japanese NAND flash memory plant with Toshiba.

Representatives for Permira and Bain Capital were not immediately available for comment. Western Digital has declined to comment.

Reuters, Agence France-Presse