NTT DoCoMo Inc. said Thursday its group net profit for the fiscal half plummeted 95.3 percent year-on-year to 4.17 billion yen, due to hefty appraisal losses on its overseas investments.

On an unconsolidated basis, the nation's largest cell phone operator, majority owned by Nippon Telegraph and Telephone Corp., posted a net loss of 168.35 billion yen, compared with a loss of 27.81 billion yen a year earlier.

DoCoMo said it took a midterm charge of 307.8 billion yen in writing off valuation losses at three overseas carriers -- 167.6 billion yen at AT&T Wireless Services Inc of the U.S., 67.9 billion yen at KPN Mobile N.V. of the Netherlands and 72.2 billion yen at Hutchison 3G U.K. Holdings Ltd.