Softbank saw its net profit jump to JPY 313.7 billion in the fiscal first quarter to June from JPY 5.5 billion a year earlier, thanks largely to gains on its investments in companies such as Flipkart and WeWork and the spin-off of ARM's Chinese business. Net sales rose 4 percent to JPY 2.273 trillion, and adjusted EBITDA was up 3 percent to JPY 721.8 billion, according Telecompaer. The underlying growth came largely from its domestic business in Japan, where EBIT increased 10 percent to JPY 221.8 billion. Adjusted free cash flow at the domestic telco business, which Softbank is spinning off as a separate company, more than doubled, to JPY 154 billion from JPY 69.1 billion a year ago.

The operator ended the period with 42.9 million mobile customers, including Line Mobile and Y! Mobile, up by 293,000 from the end of 2017. Churn reduced slightly, and device sales remained strong, at nearly 2.5 million, while ARPU fell slightly to JPY 4,320.

Broadband subscribers rose by 180,000 in the three months to 7.219 million, as growth in Hikari fibre customers continued to offset the loss of DSL subscribers. The nearly 5.3 million Hikari subscribers generated ARPU of JPY 4,590, up slightly from the previous quarter but down from JPY 4,640 a year ago.

Softbank's quarterly growth was also supported by higher ad revenues at Yahoo Japan, which grew 8 percent to JPY 76.4 billion, including a 14 percent increase in search revenues. ARM reported revenues down nearly 12 percent to JPY 41.5 billion due to the Chinese deal, while shipments of ARM-based chips were up 17 percent year-on-year to 5.5 billion.