Sony Bonds are Now Junk

Moody's said it expected earnings from Sony's core businesses to continue to face "significant" downward pressure.

It said it was especially concerned about the firm's TV and personal computer (PC) business, both of which face "intense" global competition.

Sony, which has been struggling for some time now, lowered its full-year profit forecast by 40% in October.

It said at the time that it expected to make a net profit of 30bn yen ($290m; £177m) in the financial year to 31 March 2014. That was down from its earlier projection of 50bn yen.

"The rating actions reflect Moody's view that, while Sony has made progress in its restructuring and benefits from continued profitability in several of its business segments, it still faces challenges to improve and stabilise its overall profitability," Moody's said in a statement.

Moody's downgraded Sony's rating to Ba1 from Baa3.