The Tokyo-listed investment group has become one of the most closely watched proxies for AI demand after committing tens of billions of dollars to OpenAI and building exposure across chips, power infrastructure, robotics and data-centre supply chains. The latest rally extended a sharp two-session advance that added tens of billions of dollars to SoftBank’s market value, marking one of its strongest runs since the technology boom that first made the group a symbol of risk-taking capital.
Investor enthusiasm has been driven by two linked expectations. OpenAI is preparing for a confidential US initial public offering filing that could set up a listing as early as September, while SB Energy, a power and data-centre infrastructure company backed by SoftBank and OpenAI, has said it intends to confidentially file for a US IPO. Together, the developments have strengthened the market view that SoftBank’s private holdings may be moving closer to public-market price discovery.
SoftBank’s OpenAI position is the main driver of that reassessment. The group has invested $34.6bn in the ChatGPT maker since September 2024 and has agreed to make a further $30bn investment through SoftBank Vision Fund 2. Completion of those tranches would lift its cumulative investment to $64.6bn for an ownership interest of about 13 per cent. The preferred shares are designed to convert automatically into common shares if OpenAI completes an IPO or related listing transaction.
OpenAI’s valuation has become central to SoftBank’s investment case. The company was valued at $852bn in private markets and preliminary discussions around a listing have included the possibility of a valuation as high as $1tn. The company is also seeking to raise at least $60bn at the lower end of earlier discussions, reflecting the huge capital needs of frontier AI model development, data centres, chips and power supply.
The OpenAI bet has already reshaped SoftBank’s earnings profile. The group reported a sharp profit rebound, helped by valuation gains tied to OpenAI, and said cumulative gains on the investment had reached $45bn. Its annual profit of about ¥5tn was described by the company as the highest recorded by a Japanese company, underscoring how quickly Son’s AI strategy has altered investor perceptions after years of scrutiny over the Vision Fund’s uneven performance.
SB Energy has added another layer to the rally because its business sits at the intersection of AI and power infrastructure. Founded in 2019, the company develops large-scale energy and data-centre projects and has positioned itself to benefit from surging electricity demand linked to AI workloads. It has raised more than $18bn in project capital and has a portfolio of about 5 gigawatts of operating and under-construction energy assets.
The company’s January partnership with OpenAI under the Stargate initiative placed it inside a broader push to build AI and energy infrastructure in the United States. That has made SB Energy more than a conventional renewable power developer in the eyes of investors. Its appeal rests on the argument that AI expansion will require dedicated power generation, grid connections and purpose-built campuses capable of supporting high-density computing.
SoftBank’s rally has also been supported by strength in Arm Holdings, the UK chip designer in which the group holds a large stake. Arm remains a key public asset for SoftBank and is viewed as a beneficiary of AI-related semiconductor demand. Gains in Arm shares have helped reinforce confidence that SoftBank owns multiple assets tied to the same structural theme, rather than a single concentrated wager on OpenAI.
The optimism carries risks. OpenAI faces intensifying competition from Alphabet’s Gemini, Anthropic’s Claude and other model developers, while the cost of training and operating advanced AI systems continues to rise. Credit analysts have raised concerns that the size of SoftBank’s OpenAI commitment may affect liquidity and asset quality, particularly as the group uses loans, asset sales and financing backed by holdings such as Arm and SoftBank Corp. to fund its strategy.
SoftBank arranged a $40bn bridge loan in March and drew $20bn in April, largely for the OpenAI investment, while also repaying part of that borrowing. The group has sold stakes in holdings including Nvidia and T-Mobile, issued bonds and considered other financing options as it reallocates capital towards AI. Chief Financial Officer Yoshimitsu Goto has said the group may also explore ways to use its OpenAI assets for financing if market conditions allow.
