Masayoshi Son struck a defiant tone after his SoftBank Group Corp. reported an enormous loss from investments in money-losing startups WeWork and Uber Technologies Inc.

The Japanese billionaire paced a stage in Tokyo on Wednesday showing off dozens of slides that he argued demonstrate the promise of his deal-making. He began by flashing a slide of newspaper headlines and mocking reports that SoftBank or WeWork or both would end up going bankrupt.

“There was a problem with my own judgment, that’s something I have to reflect on,” he said, looking more sober than usual in gray suit, white shirt and pink tie. “But let me explain the facts.”

SoftBank recorded an operating loss of 704.4 billion yen (US$6.5 billion) after writedowns in WeWork and other investments, the Japanese company’s first such loss in 14 years. The US$100 billion Vision Fund, the unprecedented investment fund that had been producing big profits, lost 970.3 billion yen. “Today’s earnings are a mess,” Son said. “It’s red all over.”

The company’s founder quickly shifted to defend his approach, highlighting the potential of his technology investments and boasting about his returns compared with traditional venture capitalists. He made it crystal clear that he has no plans to back off a strategy that has rattled Silicon Valley and raised concerns of a bubble in startup valuations. Indeed, he said that fundraising for a second Vision Fund is on track and the fund will debut soon.

“There is no change in our journey, no change in our vision,” Son said.

That certitude may rattle investors given the WeWork fiasco. SoftBank and the Vision Fund had invested more than $10 billion in the co-working giant ahead of its planned initial public offering in September, pushing its valuation as high as US$47 billion. But investors balked at buying shares in the money-losing startup and WeWork pulled its IPO. That left the company desperate for cash, prompting SoftBank to extend a US$9.5 billion rescue package and take an 80 per cent stake in the company. WeWork’s valuation sank to less than US$8 billion in the bailout. SoftBank shares are down 28 per cent from their peak this year.

“The explanation for the massive rescue for WeWork was unsatisfying,” said Makoto Kikuchi founder of Myojo Asset Management Co. “If SoftBank is to go on as an investment company, it needs to do a better job explaining its own governance to investors.”

Son said he had learned several lessons from the episode -- that he had put too much faith in WeWork founder Adam Neumann and that startups needed to have solid governance and a path to profits. Son vowed that there would be no more bailouts of startups in SoftBank’s portfolio.

He expressed confidence that SoftBank will be able to salvage the troubled business. As SoftBank’s Marcelo Claure takes over as chairman of WeWork, the startup will get rid of unprofitable businesses, cut expenses in half and halt new building developments. WeWork’s Japan business is already profitable, a model of what is possible. “Absolutely no problem,” Son said, eliciting laughs from skeptical investors.

“We don’t need to do anything tricky or invent anything,” he said. “Time will take care of things. Let it ripen and we will reap a profit.”

Son showed no sign of lost confidence. He said that his returns are about twice the average for venture capital.

SoftBank has pushed up valuations throughout the startup world, squeezing out the traditional venture firms of Silicon Valley and raising concerns of a bubble that will wipe out returns. It has backed ByteDance Inc., the most valuable startup in the world at $75 billion, and the second-most valuable, China ride-hailing giant Didi Chuxing. But several startups have had trouble living up to their private market valuations, including WeWork and Uber. The U.S. ride-hailing company has tumbled more than 35 per cent from its IPO in May.

Son plans to keep making his investments. The second Vision Fund is on track to close soon, he said. It was originally planned to be larger than the first fund, but it’s likely to be about the same size now because investors are more careful about the market. He also said he still plans a third fund.

“I learned a harsh lesson and I should have known better,” Son said. “But I don’t regret it too much. I won’t be too nervous about future investments. I am staying confident.”

--With assistance from Gearoid Reidy, Shelly Banjo and Kazu Hirano.