SoftBank completes OpenAI $40B commitment: structure and infra signals

Introduction

TL;DR

• On 2025-12-31, SoftBank disclosed it completed an additional $22.5B investment in OpenAI at the second closing, fully satisfying its March 2025 commitment of up to $40B.
• SoftBank also stated its aggregate ownership in OpenAI is now ~11%, and that the overall round (including third-party co-investors) was fully funded at $41B.
• OpenAI’s official March 2025 post said the funding supports scaling AI research and compute infrastructure.

1) What “completed $40B investment” means in concrete terms

SoftBank’s 2025-12-31 press release is the cleanest primary source: it says SoftBank completed an additional $22.5B investment on 2025-12-26 (U.S. time) at the second closing, thereby fulfilling the up-to-$40B commitment made on 2025-03-31 (U.S. time).

Reuters also reported the completion (via CNBC sourcing) as a major late-2025 AI funding milestone.

Why it matters: This is not just “big money”—it’s an officially confirmed second closing, meaning the capital is no longer a headline but a completed funding event with downstream operational implications.

2) Timeline and fact sheet (two-closing structure)

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flowchart TD
  A[SoftBank commitment: up to $40B] --> B[1st close (Apr 2025): $7.5B via SVF2]
  A --> C[2nd close (Dec 2025): $22.5B via SVF2]
  D[3rd-party co-investors: $11B total] --> E[Total round: $41B fully funded]
  B --> F[OpenAI Global]
  C --> F
  E --> F
  F --> G[Compute infra scaling]
  F --> H[Research acceleration]
  F --> I[Product/tool delivery]

Why it matters: In AI platform engineering, when capital lands matters as much as how much—closing events often precede large-scale compute procurement and capacity expansion.

3) Deal mechanics: conditional structure and instrument choice

SoftBank’s April 2025 release described a conditional two-step structure and the use of Convertible Interest Rights, tied to recapitalization (“economic waterfall”) conditions for OpenAI Global’s for-profit structure.

SoftBank’s December 2025 release then confirms the second closing was completed, turning the previously outlined structure into executed reality.

Why it matters: This is a template for how mega-rounds can be structured: tranches + conditions + convertible instruments, which affects governance, timing, and operational planning.

4) The infrastructure angle: compute scale and “Stargate”

OpenAI’s official post states the funding enables scaling compute infrastructure and pushing the frontier of AI research.

SoftBank’s April 2025 release explicitly ties the partnership to dedicated AI infrastructure efforts (“Stargate Project”).

Why it matters: AI competition is increasingly constrained by physical realities—power, GPUs, networks, and data centers—so funding + infra strategy must be read together.

Conclusion

• SoftBank’s 2025-12-31 press release confirms the second closing and completion of its up-to-$40B commitment to OpenAI.
• SoftBank states ~11% ownership and that the overall round was fully funded at $41B including co-investors.
• OpenAI’s official note frames the funding as a lever for research and compute infrastructure scaling.

Summary

• Second closing completed: +$22.5B (SoftBank statement)
• Commitment satisfied: up to $40B (SoftBank)
• Fully funded round: $41B including co-investors (SoftBank)
• Stated use: research + compute infra scaling (OpenAI)

Recommended Hashtags

#OpenAI #SoftBank #AIInfrastructure #Compute #DataCenter #GenAI #LLM #Stargate #VentureFunding #CloudStrategy

References

• (Completion of Additional $22.5 Billion Investment in OpenAI, 2025-12-31)[https://group.softbank/en/news/press/20251231]
• (SoftBank has completed its $40 billion investment in OpenAI source says, 2025-12-30)[https://www.reuters.com/business/media-telecom/softbank-has-fully-funded-its-40-billion-investment-openai-cnbc-reports-2025-12-30/]
• (Announcement Regarding Follow-on Investments in OpenAI, 2025-04-01)[https://group.softbank/en/news/press/20250401]
• (New funding to build towards AGI, 2025-03-31)[https://openai.com/index/march-funding-updates/]
• (Investor Briefing Q2 FY2025, 2025-11-11)[https://group.softbank/media/Project/sbg/sbg/pdf/ir/presentations/2025/investor-presentation_q2fy2025_01_en.pdf]
• (SoftBank completes commitment to OpenAI, Times of India)[https://timesofindia.indiatimes.com/technology/tech-news/softbank-completes-its-commitment-to-chatgpt-maker-openai-for-which-it-sold-nvidia-shares-worth-5-83-billion-report/articleshow/126256127.cms]
• (Biggest AI deals of the year 2025, Business Insider)[https://www.businessinsider.com/biggest-ai-deals-acquisitions-of-the-year-2025-12]