SoftBank Group has finalized its full $40 billion funding commitment to OpenAI, marking one of the largest private technology investments in history. The Japanese conglomerate delivered a final tranche of approximately $22 billion to $22.5 billion last week, following earlier infusions of $8 billion in direct capital and $10 billion via syndicated co-investment. This milestone represents the culmination of an agreement reached in March to back OpenAI’s for-profit subsidiary with both direct and partner-sourced funds.

By completing this investment, SoftBank secures a stake exceeding 10 percent in OpenAI. The deal initially valued OpenAI at around $300 billion on a post-money basis; subsequent secondary transactions in October pushed that valuation closer to $500 billion, according to PitchBook data. SoftBank’s $40 billion commitment included direct capital deployment and coordination with strategic backers, underscoring the firm’s ability to marshal large-scale syndications for marquee AI ventures.

The investment dovetails with SoftBank’s broader strategy to build out AI-focused infrastructure, particularly data centers and connectivity. OpenAI has partnered with SoftBank and Oracle on a multiyear data-center program dubbed “Stargate,” aimed at supporting next-generation AI models with massive compute capacity. Masayoshi Son, SoftBank’s chairman and CEO, has emphasized that physical infrastructure—compute, power and network—will be critical to maintaining leadership in artificial intelligence deployment across industries.