TOKYO—After a deal that could have been worth $80 billion to his company fell apart, SoftBank Group Corp. Chief Executive Masayoshi Son is playing salesman for Plan B—an initial public offering of chip designer Arm.
Mr. Son sounded as if he were on a roadshow for investors at a news conference in Tokyo on Tuesday. He said Arm is entering a “golden period” of high demand for the chips it helps create in smartphones, electric vehicles and computer-server farms operated by the likes of Amazon.com Inc.