Japanese telecommunications operator NTT DoCoMo Inc. said Wednesday that it will write off ¥573 billion (US$4.68 billion) of losses on its overseas investments for the first half of the year, including revaluing its Dutch investment in KPN Mobile NV at zero.

For April 1. to Sept. 30, NTT DoCoMo will recognize and post impairment losses of ¥399 billion for AT&T Wireless Services Inc., ¥126 billion for Hutchison 3G UK Holdings Ltd. and ¥108 billion for KPN Mobile, it said in a statement.

This is in order to reflect drops in the share prices of the companies, or the "fair value" of the shares, it said.

NTT DoCoMo wrote off an even larger sum, about ¥950 billion, on its overseas investments last year. This years' losses mean that the company has now lost almost two thirds of its ¥1.9 trillion investment in overseas carriers.

An earnings forecast, showing the effects of the write-offs, is likely to be issued in November, NTT DoCoMo said.