SoftBank Group completed its $40 billion investment in OpenAI this week, according to CNBC reports citing people familiar with the matter. The Japanese conglomerate delivered a final payment of $22 billion to $22.5 billion to the ChatGPT maker, closing one of the largest private technology investments ever made.
The investment gives SoftBank more than 10% ownership in OpenAI, which is now valued at approximately $260 billion pre-money. This follows earlier investments of $8 billion directly from SoftBank and $10 billion syndicated from other backers, according to multiple sources. The deal was first outlined in March 2025 when SoftBank agreed to lead the funding round.
To finance the massive commitment, SoftBank executed significant portfolio adjustments earlier this year. The company liquidated its entire $5.8 billion stake in Nvidia and sold $9.17 billion worth of T-Mobile shares. SoftBank CFO Yoshimitsu Goto stated the company "can still maintain financial strength" through these strategic moves.
A substantial portion of the $40 billion investment will support Project Stargate, a joint AI infrastructure venture between OpenAI, SoftBank, and Oracle announced earlier this year. The multi-year data center initiative aims to build a nationwide U.S. network specifically designed for AI workloads. SoftBank is also collaborating with OpenAI on a separate AI data center in Japan scheduled for 2026.
OpenAI's valuation trajectory shows remarkable growth, with the company reaching around $300 billion post-money from this SoftBank deal. A secondary stock sale completed in October valued OpenAI at approximately $500 billion, according to Pitchbook data. The AI firm continues to attract major partnerships, including a recent $1 billion investment from Disney alongside a three-year licensing agreement for its Sora video model.
Masayoshi Son, SoftBank's founder and CEO, has positioned artificial intelligence as the central focus of his investment strategy. The company recently acquired data center investment firm DigitalBridge for $4 billion to strengthen its physical AI infrastructure. Son reportedly expressed emotional difficulty with selling Nvidia shares, stating he "was crying" but needed capital for OpenAI and other AI projects.
The investment completion comes as AI dominates global technology markets, driving unprecedented spending by major corporations. OpenAI has emerged as a central pillar in this industry-wide push, with its technology partnerships extending across semiconductor manufacturers, cloud providers, and entertainment companies. SoftBank's stock has gained 98% year-to-date, reflecting investor confidence in Son's AI-focused strategy.
