SoftBank Group shares surged more than 16% in a single session on May 21, adding over $35 billion in market capitalization after the Japanese conglomerate's Vision Fund reported a $46 billion annual gain -- the largest in its history. The fund's performance was overwhelmingly driven by a single position: OpenAI, whose valuation has surged from $80 billion to over $300 billion as the AI company's revenue accelerated past $20 billion annualized.
The rally extended the following day with shares climbing an additional 11.9%, making SoftBank one of the best-performing large-cap stocks globally over a two-day period. The surge was amplified by Nvidia's record Q1 earnings, which lifted SoftBank's majority-owned Arm Holdings and validated the AI infrastructure thesis that underpins much of the Vision Fund's portfolio. SoftBank's total market capitalization now exceeds $230 billion.
What happened
SoftBank's Vision Fund reported its annual results for the fiscal year ending March 2026, posting a $46 billion net gain -- a dramatic reversal from the $32 billion loss recorded in fiscal year 2023. Approximately $45 billion of the gain came from the appreciation of SoftBank's stake in OpenAI, which the company first acquired in late 2023 and has steadily increased through subsequent funding rounds. The Vision Fund also benefited from public market gains in Arm Holdings, whose shares have more than doubled from their September 2023 IPO price.
CEO Masayoshi Son used the earnings call to reaffirm his vision of SoftBank as the world's leading AI infrastructure investor. He announced plans to deploy an additional $50 billion into AI-adjacent companies over the next two years, focusing on data center infrastructure, AI chip design, and enterprise AI applications. Son described the current moment as 'the beginning of the beginning' of the AI revolution.
Why it matters
SoftBank has become the single largest proxy play for the AI infrastructure boom. Its portfolio includes majority ownership of Arm