Key Points:
- SoftBank Group shares rose nearly 13% in Tokyo, reaching a record close of 8,000 yen during a massive four-day rally.
- The stock surge added over $60 billion to SoftBank’s market value, carrying Japan’s Nikkei 225 index past 65,000 points.
- The rally reflects optimism over SoftBank’s 90% stake in Arm Holdings, which jumped on Nvidia’s blockbuster earnings.
- Investors are piling in ahead of potential public listings for portfolio stars OpenAI and SB Energy.
Japanese technology investment giant SoftBank Group Corporation (TYO:9984) saw its shares surge to a record high on Tuesday, May 26, 2026. The stock jumped nearly 13% during intraday trading to touch the milestone level of 8,000 yen, extending its winning streak into a fourth consecutive session. The historic rally, which has added over $60 billion to SoftBank’s market capitalization over the past fortnight, also carried Japan’s benchmark Nikkei 225 index above the 65,000-point threshold for the first time in history.
The massive capital inflow reflects intense global optimism about SoftBank’s unique, highly concentrated exposure to artificial intelligence (AI) infrastructure. Specifically, investors are bidding up SoftBank shares to gain exposure to British semiconductor designer Arm Holdings, of which SoftBank retains a dominant 90% ownership stake. Following the blockbuster earnings report from AI bellwether Nvidia Corporation last week, Arm’s shares surged more than 30% in just two trading days, directly boosting the value of SoftBank’s equity portfolio.
As a result of this rapidly growing valuation, prominent research firm SMBC Nikko raised its price target for SoftBank Group to 8,500 yen from its previous estimate of 5,200 yen. Analysts explained that ARM’s power-efficient CPU architectures are becoming the preferred choice for hyperscale cloud providers and modern AI data centers. Because SoftBank’s majority stake in Arm now accounts for roughly 40% of its total asset value, any upward re-rating of the semiconductor company has an outsized, highly leveraged impact on the Japanese parent’s net asset value.
In addition to the semiconductor boom, speculation surrounding a potential public market debut for ChatGPT creator OpenAI is fueling the massive rally. Financial industry reports suggest that investment bankers are currently assisting OpenAI with a draft prospectus for a confidential initial public offering (IPO) filing, targeting an official public debut as soon as this autumn. The generative AI pioneer, privately valued at over $850 billion during its most recent funding round, could become one of the most valuable companies in the world upon listing.
SoftBank has positioned itself as one of OpenAI’s largest and most influential shareholders. Earlier this year, the Tokyo-based conglomerate agreed to invest an additional $30 billion in the startup in phases, bringing its total commitment to a staggering $64.6 billion. This massive cash injection will give SoftBank an estimated 13% ownership stake in OpenAI by October 2026. During the March quarter alone, the Japanese investment firm recorded a stellar book gain of $25 billion on its OpenAI holdings, demonstrating the massive wealth-creation capabilities of founder Masayoshi Son’s “all-in” AI investment strategy.
Beyond software and silicon, SoftBank is also building out the physical infrastructure required to power the global AI revolution. Its jointly owned power generation and grid management subsidiary, SB Energy Corporation, is also reportedly moving toward a confidential U.S. IPO. SB Energy has raised more than $1.8 billion in funding over the past year to build a massive, 10-gigawatt data center campus in Ohio. Once complete, this clean energy campus will exceed the combined installed data center power capacity of the United Kingdom, Japan, and South Korea, providing a secure, long-term foundation for future AI processing clusters.
The consecutive record-breaking sessions have narrowed SoftBank’s historical net asset value discount. Between mid-2019 and mid-2025, the investment firm traded at an average discount of nearly 50% compared to the value of its underlying assets, largely due to high-profile writedowns within its Vision Fund portfolio, including the collapse of WeWork. However, over the past year, intense investor appetite for pure-play AI assets has successfully narrowed this valuation gap, proving that public markets now view SoftBank as an indispensable proxy for the global AI ecosystem.
This spectacular financial turnaround has also significantly boosted the personal fortune of SoftBank’s charismatic founder. The surging stock price has increased Masayoshi Son’s net worth by nearly 40% this year, pushing his personal wealth to approximately $50.1 billion. This rapid wealth creation has established Son as Japan’s second-richest person, validating his controversial decision to pivot the conglomerate away from traditional internet services toward highly speculative, high-growth AI and robotics startups.
While some conservative analysts caution that SoftBank’s high leverage, debt exposure, and the massive cash burn of its portfolio companies pose real long-term risks, the current momentum shows no signs of slowing. As long as global hyperscalers continue to spend billions of dollars on AI servers and data center infrastructure, SoftBank’s controlling stakes in both Arm and OpenAI will remain highly sought after by international investors. By successfully anchoring itself at the absolute center of the digital revolution, the Japanese conglomerate has secured an irreplaceable position in the global technology market.
