HOW WE DID IT
The transaction was extraordinarily complex given, among other things, OpenAI’s non-traditional and evolving organizational structure.
This necessitated creativity because traditional venture fundraising methods (such as issuing preferred stock) were not available. Instead, a bespoke, purpose-built investment instrument (called a convertible interest right) was negotiated to set forth the parties’ rights and restrictions.
Moreover, the overall size of the round was made contingent on OpenAI completing a recapitalization by the end of 2025, which was successfully completed when the company turned into a public benefit corporation in October 2025, unlocking the full size of the round.
Background
With the new funding, as a result of MoFo's strategic counsel and SoftBank's vision and capability to scale transformative technologies, OpenAI is positioned to “continue building AI systems that drive scientific discovery, enable personalized education, enhance human creativity, and pave the way toward AGI that benefits all of humanity.”1
Masayoshi Son, Chairman & CEO of SoftBank Group Corp., said: “We are deeply aligned with OpenAI’s vision of ensuring AGI benefits all of humanity.”2
The Result
MoFo Team
Ken Siegel
Partner, Tokyo
Partner, San Francisco
Chris McKinnon
View Ken's
Bio
View Chris's
Bio
MoFo Team
Result
Background
SoftBank
CASE STUDY
Client Name
Title, SoftBank
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Advising Visionaries on the Frontier of Artificial Intelligence
Signing of definitive investment agreement for 2025 investment round
MARCH 31, 2025
Initial investment of $7.5 billion by SoftBank
APRIL 2025
OpenAI completes recapitalization
OCTOBER 28, 2025
Remaining investment of $22.5 billion by SoftBank
DECEMBER 26, 2025
FUNDING TIMELINE
Over several decades, Morrison Foerster (MoFo) has partnered with SoftBank, one of the most influential and active technology investors, on some of the largest and most complex business transactions around the globe.
Building upon a strong collaborative foundation, the MoFo-SoftBank partnership reached a historic new milestone with MoFo advising SoftBank on its record-breaking investment in OpenAI, the world’s leading artificial intelligence research and deployment company.
MoFo advised SoftBank as lead investor in the 2025 venture financing of OpenAI, breaking numerous records.
Stephen Lam
Managing Partner and General Counsel, SoftBank Group International
Simply put, no firm understands SoftBank’s unique style and way of doing deals better than MoFo. That is a testament to their deep expertise in technology M&A, AI and global reach, and also to the longstanding trusted partnership between MoFo’s dedicated SoftBank team and our internal legal team, which has been forged through many years of working closely on our most important deals. This shared history ensured that we were able to navigate the intricacies of this historic deal with confidence and precision, despite the unique issues raised and challenging timeline. We are grateful for their unwavering commitment and strategic partnership throughout the process and look forward to many more opportunities to collaborate going forward.
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Overall round size
SoftBank investment
30
Co-investors' investment
11
billion
billion
billion
Chair, San Francisco
Eric McCrath
View Eric's
Bio
Partner, San Francisco
Suz Mac Cormac
View Suz's
Bio
Partner, New York
Joe Sulzbach
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Bio
Partner, San Francisco
Aya Eguchi
View Aya's
Bio
41
The transaction was a global effort across MoFo practices and industries—including Mergers + Acquisitions, Private Equity Investments + Buyouts, Emerging Companies + Venture Capital, Technology Transactions, and Artificial Intelligence (AI)—drawn from 13 of the firm’s offices.
London
Tokyo
Brussels
Boston
New York
Washington, D.C.
Miami
Austin
Denver
San Francisco
Palo Alto
Los Angeles
SoftBank Was Lead Investor in $41 Billion Investment Round in OpenAI
Largest investment round by a venture-backed startup in history
Largest single venture investment by an investor in startup history
Made OpenAI one of the most highly valued venture-backed startups in the world
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MoFo Global Office Involvement
Tokyo
Berlin
Brussels
London
Boston
New York
Washington, D.C.
Miami
Austin
Denver
San Francisco
Palo Alto
Los Angeles
MoFo Global Office Involvement