NTT DoCoMo Inc, Japan's biggest mobile-phone operator, said it will invest US$10 million in a fund targeting Chinese telecommunications and media companies, to expand its revenue sources.

The US$120 million Gobi Fund II LP will start investing this month in startup companies such as Internet content providers in China, whose economic growth is "promising," Tokyo-based DoCoMo said in a statement yesterday. The fund has an investment period of 10 years, Bloomberg News reported.

The move builds on DoCoMo's plan to purchase stakes in companies overseas to speed up expansion and follows a US$10 million investment in the Gobi Fund I in December 2003. The company, which reported a second straight profit decline in the year just ended, aims to diversify its earnings sources as growth slows in the country's US$74 billion market, where about three quarters of people use mobile phones.