(Reuters) - Japan's Nippon Steel Corp is set to book 80 billion yen ($1 billion) in extraordinary losses in the April-June quarter after the Sumitomo Metal Industries Ltd shares it holds fell in value, the Nikkei business daily said on Saturday.
Nippon Steel and Sumitomo Metal, Japan's No.1 and No.3 steelmakers respectively, will merge in October to become the world's No.2 steelmaker.
The loss would be the latest headache for Nippon Steel, trying to recover after having booked in the January-March period its smallest quarterly profit since effects of the Lehman credit crisis began to hit steelmakers in 2009.
Nippon Steel could not be reached immediately for comment.
Nippon Steel holds 451.8 million Sumitomo Metal shares, according to its securities report.
Sumitomo Metal shares ended at 130 yen on Friday, which means the current total value of the shares held by Nippon Steel is about 58.7 billion yen.
The book value of the these shares are about 140 billion yen, or more than double the current value, the Nikkei reported without citing a source. Under accounting rules, that would force Nippon Steel to book the loss, the Nikkei said. ($1 = 79.7900 Japanese yen)