OpenAI Raises $40 Billion SoftBank-Led Round at $300B Valuation
Summary
OpenAI closed a $40 billion funding round led by SoftBank at a $300 billion post-money valuation — the largest private technology fundraise in history at the time. SoftBank committed $30 billion as lead investor. The deal was structured in two tranches, with the second $30 billion contingent on OpenAI completing its for-profit restructuring into a Public Benefit Corporation by December 31, 2025. SoftBank completed the final $22.5 billion tranche on December 30, 2025.
What Happened
OpenAI announced the close of a $40 billion funding round on March 31, 2025, at a $300 billion post-money valuation. The round was led by SoftBank Group, with Masayoshi Son personally championing the investment. Microsoft participated as a co-investor alongside other undisclosed participants.
The deal was structured in two tranches. The initial tranche closed immediately; the second tranche of $30 billion from SoftBank was contingent on OpenAI completing its conversion from a capped-profit LLC structure into a Delaware Public Benefit Corporation by December 31, 2025. This structure created a direct financial incentive — $30 billion — for OpenAI to complete its corporate restructuring on a defined timeline.
The $300 billion valuation was a significant step up from OpenAI's prior valuation of approximately $157 billion from an October 2024 round. The tripling of valuation over roughly five months reflected both ChatGPT's commercial growth and investor conviction about the trajectory of AI capabilities.
SoftBank's lead position connected OpenAI to Masayoshi Son's long-running thesis on artificial superintelligence, which he had articulated publicly for several years. Son had previously invested in AI through SoftBank's Vision Fund but had not been a major direct investor in frontier AI labs. The OpenAI deal represented a significant concentration of SoftBank capital in a single AI bet.
On December 30, 2025, one day before the deadline, SoftBank completed the final $22.5 billion tranche following OpenAI's completion of the PBC restructuring on October 28, 2025.
Why It Matters
The $40 billion SoftBank round marked a structural shift in how AI labs are capitalized. Previous AI funding rounds, while large, had been measured in the low billions. A $40 billion single round at $300 billion valuation placed OpenAI in the same valuation tier as major public technology companies — despite having no public shares and, at the time, significant operating losses.
The deal's structure was consequential: by making $30 billion contingent on completing the PBC restructuring, SoftBank's investment created binding financial pressure that accelerated OpenAI's corporate transformation. Whether SoftBank intended this as governance influence or simply needed the restructuring to make their equity stake work in their fund structures, the practical effect was to set a hard deadline for a governance change that had been debated and delayed for months.
The round also validated a new category of investor for frontier AI: sovereign and quasi-sovereign capital. SoftBank, with roots in Japanese telecommunications and a global investment mandate, represented a different capital source than typical Silicon Valley venture funds. This pattern — strategic and national capital flowing into AI labs alongside traditional VC — would intensify through 2025 and 2026.