SoftBank Completes $40B OpenAI Investment

According to people familiar with the matter, SoftBank Group has completed a US$40 billion investment in OpenAI, marking one of the largest private funding rounds ever and reinforcing founder Masayoshi Son's long-term bet on artificial intelligence.

SoftBank has been steadily building one of the world’s largest private technology investment portfolios, with a strong focus on AI and the infrastructure behind it, including large-scale data centers. By 2025, AI has become the central driver of the global technology market, triggering a new wave of investment from major corporations and reshaping investor expectations worldwide.

In March 2025, SoftBank agreed to invest up to US$40 billion in a for-profit subsidiary of OpenAI. The funding combines direct capital from SoftBank with co-investments from other participants. Data from PitchBook indicates the deal initially valued OpenAI at around US$300 billion post-investment. However, a secondary share sale completed in October later pushed the company's valuation to approximately US$500 billion.

Sources noted that OpenAI had previously raised US$10 billion, with SoftBank contributing US$8 billion. This was followed by an additional SoftBank-backed investment estimated at US$22–22.5 billion, further strengthening OpenAI's financial position. As a result, OpenAI has become a key pillar of the broader AI investment boom across the tech industry.

Beyond funding, OpenAI is also collaborating with Oracle and other partners on the “Stargate” project—a massive, multi-year data center initiative designed to support next-generation AI models. The project has attracted backing from major investors, including SoftBank, highlighting the growing importance of AI infrastructure alongside model development for the future of advanced computing.