In what could be the largest tender offer for a Japanese firm in corporate history, telecom giant Nippon Telegraph and Telephone Corp. (NTT) said Tuesday it will buy all shares of its subsidiary and mobile phone unit NTT Docomo Inc. in an eye-popping ¥4.3 trillion takeover bid.

The deal between the two, which would give NTT Docomo solid financial backing to engage in price wars, may trigger even more intense competition among the nation’s major wireless carriers.

While the suggestion was disputed Tuesday by NTT President Jun Sawada, the deal was reportedly prompted by pressure from the new administration led by Prime Minister Yoshihide Suga to lower mobile phone charges. The government is NTT’s largest shareholder, owning around 34 percent of the corporation as of June.