SoftBank Group said it executed the third and final $10.0 billion tranche of its follow-on investment in OpenAI on 1 October 2026, via SoftBank Vision Fund 2, completing the $30.0 billion it announced on 27 February. Its cumulative investment in OpenAI now totals $64.6 billion, for an ownership interest of approximately 13%, SoftBank says.
SoftBank says the third tranche was funded with proceeds from foreign currency-denominated senior notes announced on 24 September, and that all borrowings under its bridge facility have now been repaid.
Business Pill · CONVERTIBLE PREFERRED
A short explainer of convertible preferred shares: paid first, able to turn into common shares. It teaches the general idea only and says nothing about any company in this story.
The key insight: As we read it, the notable change is in how SoftBank paid rather than how much. The first two tranches were funded from a bridge facility and the third from senior notes, and SoftBank says all bridge borrowings are now repaid, in line with the plan it set out in February.
According to SoftBank’s releases, the first $10.0 billion tranche was executed on 1 April 2026 and the second on 1 July, each funded with $10.0 billion of borrowings under a bridge facility agreement entered into on 27 March.
The third tranche was funded differently, with the senior notes. Effective 30 September, SoftBank says it canceled the remaining $10.0 billion of undrawn capacity under the $40.0 billion bridge facility, following an early repayment it announced on 9 September, so no undrawn commitments remain.
SoftBank’s cumulative investment in OpenAI, US$ billion, per its releases: $64.6 billion after the third tranche on 1 October 2026; the pre-follow-on $34.6 billion is stated in its February release.
The Same Dollars, Different Yen
SoftBank’s releases convert each $10.0 billion tranche into yen at a stated conversion rate: JPY 1,588.7 billion in April, JPY 1,627.3 billion in July and JPY 1,579.6 billion in October.
On our arithmetic, those three conversions add up to about JPY 4,795.6 billion, against JPY 4,674.3 billion for the full $30.0 billion at the conversion rate in the February announcement. These are SoftBank’s stated conversion rates, not necessarily its actual funding cost.
Per SoftBank’s release of 1 October 2026: ownership of approximately 13%; a $30.0 billion follow-on in three $10.0 billion tranches; all bridge borrowings repaid and the remaining $10.0 billion of capacity canceled.
Terms in the February Announcement
SoftBank’s February release puts OpenAI’s pre-money valuation for the round at $730 billion, and says SoftBank had invested an aggregate of $34.6 billion in OpenAI through SoftBank Vision Fund 2 since September 2024.
The securities are preferred shares, automatically convertible into common shares of OpenAI upon an IPO or related listing transaction, according to the release. SoftBank said its financial policies regarding loan-to-value and cash position remain unchanged, and that the OpenAI shares are measured at fair value through profit or loss each quarter.
The Structural Read
The plan was set in February. SoftBank said then that the investment would be financed initially through bridge loans and subsequently replaced over time through existing assets and other financing measures.
The stake is preferred stock. The February release says the shares convert automatically into common shares of OpenAI upon an IPO or related listing transaction.
Its value will move each quarter. SoftBank says the OpenAI shares are measured at fair value through profit or loss on a quarterly basis.
Masayoshi Son, SoftBank Group, 27 February 2026
“AI is transforming the world at an unprecedented pace.”
Three Implications
$64.6 BILLION IN TOTAL SoftBank’s cumulative investment in OpenAI is $64.6 billion, per its October release.
FUNDING SWITCHED TO NOTES The third tranche was funded with senior notes rather than the bridge facility, SoftBank says.
CLOSINGS TIED TO A LISTING The February release says closing dates may be accelerated in the event of a public listing of OpenAI shares.
The framework’s starting point describes 2026 spending by the largest technology groups as “the largest single-year concentrated infrastructure cycle in the history of technology.”
As we read it, SoftBank’s releases show one financing channel around that cycle: a holding company borrowing short-term, then refinancing with notes, to fund a model developer at its centre.
What Is Not Established
We read SoftBank’s four releases on the investment in full; we did not read the senior notes or bridge repayment releases. The releases we read give a pre-money valuation but not a price per share. We did not contact SoftBank or OpenAI.
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SoftBank has completed its $30.0 billion follow-on investment in OpenAI in three $10.0 billion tranches, bringing its cumulative investment to $64.6 billion and its ownership to approximately 13%, and says all borrowings under the bridge facility that funded the first two have been repaid, with no undrawn commitments remaining.
A note on sourcing. We read SoftBank’s four releases on the OpenAI follow-on investment in full; the yen sum is our arithmetic. We did not contact SoftBank or OpenAI. Nothing here is a forecast, and nothing here is financial or investment advice.
Gennaro Cuofano is a CRO and tech executive who has worked in AI since late 2015, starting with bringing NLP, natural-language generation, voice and chatbot products to the marketing industry. His background is in law and finance: he holds a Master's degree in Law and an International MBA with an emphasis on corporate finance (LUISS Business School and the University of San Diego, 2012), and worked as a financial analyst at a real-estate investment firm in San Diego and as an assistant controller. His work focuses on business model strategy, business engineering and, more broadly, structural analysis: how companies make money, read from their own filings. He created FourWeekMBA and leads research there and at The Business Engineer, his newsletter on AI and business strategy, with over 95,000 subscribers and more than 1,000 published analyses. His writing has also appeared on Entrepreneur (for example, How to Digitize a Family Business in Europe) and HackerNoon. Find him on LinkedIn and Substack. See how we source.
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