Nippon Telegraph and Telephone Corp. said Tuesday it has decided to make its NTT Docomo Inc. subsidiary a fully owned unit through a 4.25 trillion yen ($40 billion) tender offer, the largest-ever in Japan.With Prime Minister Yoshihide Suga pushing for significant cuts in smartphone service fees and telecom companies vying to adopt high-speed 5G networks, NTT aims through the move to build a more effective management team to guide the mobile carrier group.NTT, which had a 66.21 percent stake in the mobile phone service company as of March 31, announced it plans to acquire the remaining share…READ FULL ARTICLE