The group had retreated into a defensive stance, curbing investment activity as it booked heavy investment losses at its Vision Fund investing arm.
"The time has come to shift to offence mode," Son told shareholders at the group's annual general meeting.
SoftBank reported a net loss of 970 billion yen ($6.85 billion) for the year ended March 31, cushioning losses at the Vision Fund unit by selling down its stake in Alibaba (9988.HK).
Chief Financial Officer Yoshimitsu Goto last month said that the group wants to ensure it does not miss investment opportunities, moderating its previous emphasis on defence.
SoftBank's liquid assets, which include cash, cash equivalents and an undrawn commitment line, rose to 5.1 trillion yen at March-end compared to 2.9 trillion yen a year earlier.
Son, who has stepped back from public pronouncements in recent months, spent much of his presentation to a loyal retail investor base on Wednesday speaking about his enthusiasm for AI.
ASTRO BOY
Son said he asked ChatGPT, the AI-powered chatbot from startup OpenAI, to write new adventures for Astro Boy, the classic manga series by Tezuka Osamu.
"It's almost as if the author wrote it," he said.
The billionaire said he has spent the last eight months creating inventions that he believes can be realised through the conglomerate's chip designer Arm.
"We want to bring these inventions to fruition step by step. Arm is the key," he said.
SoftBank aims to list Arm on Nasdaq later this year and is seeking to raise between $8 billion and $10 billion, Reuters has reported. Arm is in talks with companies including Intel (INTC.O) about potential participation in the IPO.
Observers debate the ability of Son, who suffered high-profile stumbles such as his backing for office-sharing firm WeWork, to pick winners in an economy expected to be increasingly powered by AI.
Son said he invested in companies that he thought would succeed in an AI-driven society and, while there have been failures, he believes enough of his portfolio companies will succeed.
"If you have one or two out of a hundred smash hit, that will pay back everything," Son said.
"I think at least I have found more than several of them ... I think that's enough."
($1 = 141.5900 yen)
