SoftBank CEO and Sprint Chairman Masayoshi Son once again asserted his support for the U.S. operator, saying the carrier “will be the most dramatic large-scale turnaround” in U.S. history.

SoftBank spent more than $20 billion to acquire controlling interest in Sprint in 2012, and the company had initially hoped to acquire T-Mobile as well and merge the carriers to take on Verizon and AT&T, Son said during a conference call Monday discussing SoftBank’s quarterly earnings. That effort was dropped when U.S. regulators indicated they were opposed to a merger, but Son said Sprint is no longer the financial sinkhole it once was.

“For the past three years, Sprint has been a drag on our consolidated basis and was the biggest reason our debt increased,” Son said, according to a Seeking Alpha transcript. “Originally Sprint and T-Mobile, we were going to acquire them both, merge them and have a company that was equal to AT&T and Verizon…. That was our basic strategy. But because of the rejection by the U.S. government, our basic strategy did not work out. But as a result, we had difficulty (with Sprint), but we made a steady effort. And as a result, the net loss stopped…. So now we are seeing a steady increase in the number of subscribers.”

Indeed, Sprint’s customer base has grown significantly in 2016 thanks primarily to aggressive promotions such as its offer to halve the monthly bills of customers who switch from its rivals. The operator saw 347,000 net postpaid phone additions during the most recent quarter, well outpacing the 275,000 predicted by Wells Fargo Securities.

And Sprint has slowly shored up its finances as it has grown its customer base, Son said. The operator has cut costs across the board over the last year, and has noticeably reduced its network capex as it turns to small cells to densify its network.

“As a result, Sprint’s free cash flow has made a turnaround. Until now it was hundreds of billions of yen of loss every year,” Son said. “So cost is reduced. Fixed cost is reduced, capex is reduced significantly.”

Analysts have questioned whether Sprint can continue to be competitive as it cuts back its network investment, however. The operator raised eyebrows earlier this year when it lowered its capex guidance from $4.5 billion to $3 billion; it spent only $470 million in capex during the latest quarter.

“Though the company once again did not provide incremental specifics on its network strategy, management did note that it had been able to re-invigorate SoftBank Japan’s network vs. its peers, all while on a lower capital expenditure budget. Mr. Son seemed to endorse the fact that he believes the same results can be achieved in the U.S.,” Barclays analyst Amir Rozwadowski said in a research note addressing Son’s remarks. SoftBank “doesn't see the need to alter the strategy at Sprint, noting that it remains on track with both network improvement plans and cost reduction efforts. In both areas SoftBank believes there is further room for improvement…. However, questions on its ability to surpass peers on network quality -- a clear goal of its parent company -- on comparatively lower capex are likely to remain in place for now."