October 2, 2026
The short version: SoftBank Group has completed the third and final $10 billion tranche of its $30 billion follow-on investment in OpenAI, bringing its cumulative investment in the ChatGPT maker to $64.6 billion — for roughly 13% of the company.
What happened
SoftBank Group announced on October 1 (Japan time) that it had executed the final $10 billion tranche of its follow-on OpenAI investment through SoftBank Vision Fund 2, closing out a commitment first announced on February 27, 2026. The final payment totals $10.0 billion, or ¥1,579.6 billion at a conversion rate of $1 to ¥157.96, according to the company’s release.
SoftBank said the tranche was funded with proceeds from its issuance of foreign currency-denominated senior notes announced on September 24. On the same day, SoftBank also canceled the remaining $10 billion of undrawn capacity under a $40 billion bridge facility it set up in March 2026; following an earlier partial repayment announced on September 9, no borrowings or undrawn commitments remain under that facility.
The numbers behind the deal
With the third tranche complete, SoftBank’s cumulative investment in OpenAI now stands at $64.6 billion, for an ownership interest of approximately 13%. That makes the Japanese conglomerate one of OpenAI’s largest outside backers.
One number worth handling carefully: dividing $64.6 billion by 13% gives a figure near $497 billion — but that is SoftBank’s blended average cost basis across several rounds, not OpenAI’s current valuation. Reuters reported that OpenAI secured $122 billion in commitments earlier this year at an $852 billion valuation, anchored by Amazon, Nvidia, and SoftBank.
This is separate from the new up-to-$30 billion raise OpenAI is reportedly targeting at a roughly $1.4 trillion valuation, which we covered earlier this week.
Why it matters
For subscribers watching the AI money flow: this is the close of one of the largest single-company AI investments on record, and it locks in SoftBank as OpenAI’s financial heavyweight backer just as the lab is spending at a historic pace on compute infrastructure. Masayoshi Son has funded part of the bet with the largest high-yield corporate bond sale ever recorded globally — $11.1 billion raised last month, per Reuters. That’s not cautious optimism; that’s leverage. The takeaway is simple: the biggest players in AI are still betting that scale of spending is the game itself, and SoftBank just finished writing its check.
Frequently asked questions
How much has SoftBank invested in OpenAI in total?
About $64.6 billion cumulatively, giving it roughly 13% ownership of OpenAI.
Does 13% for $64.6 billion mean OpenAI is worth about $497 billion?
No. That figure is SoftBank’s blended cost basis across several funding rounds, not a current valuation of the company.
How was this final tranche funded?
With proceeds from SoftBank’s foreign currency-denominated senior note issuance announced September 24, alongside the wind-down of a $40 billion bridge facility from earlier this year.
Is this part of the new $30 billion OpenAI raise?
No. This completes a follow-on commitment announced in February 2026. The separate new raise reportedly targets a much higher valuation and remains ongoing.
Sources: SoftBank Group press release; Reuters reporting.