Japan’s largest mobile operator NTT DoCoMo has signed on to Acca Networks WiMAX venture. Acca said it will invest 30 billion yen ($258 million) in the estimated 72 billion yen ($620 million) project and will hold a 40% stake. DoCoMo will invest 19 billion yen ($164 million) and take a 26% stake.

Acca President Masaharu Kimura said the company is still in talks with other companies about its WiMAX plans, including some financial firms.