TOKYO (Reuters) - Japanese telco SoftBank Corp 9434.T said on Monday its operating profit in the quarter ended June rose 4%, in line with estimates, as the number of mobile users grew.

FILE PHOTO: The logo of SoftBank Group Corp is seen at the company's headquarters in Tokyo, June 30, 2016. REUTERS/Toru Hanai/File Photo

The company’s operating profit was 268.9 billion yen ($2.54 billion) in the first quarter, versus an average estimate of 268 billion yen from four analysts polled by Refinitiv.

Its smartphone subscribers rose 372,000 from three months earlier as SoftBank markets a plan targeting heavy data users.

The telco maintained its full-year operating profit forecast at 890 billion yen, up 9% from the previous year.

SoftBank Corp has hiked its stake in Yahoo Japan Corp 4689.T and turned the internet company into a subsidiary to drive growth outside its wireless business.

The Yahoo stake and its first ever share buyback announced last month have helped support SoftBank Corp’s shares, which debuted, and have languished, below their 1,500 yen IPO price.

The stock closed down 0.5% ahead of the earnings. SoftBank Corp had Japan's largest ever listing in December as parent SoftBank Group Corp 9984.T refocuses on technology investing.

The telco's outline for expansion includes a platform for autonomous driving that it has set up with Toyota Motor 7203.T and plans to export.

Such ventures will require the high-speed, low-latency 5G services set to begin in Japan next year and that Chief Executive Ken Miyauchi says will drive growth at the telco and calm fears that the country’s market has hit maturity.

($1 = 105.9100 yen)