SoftBank has officially wired the final $10 BILLION into OpenAI.
And the way Masayoshi Son financed this AI bet is almost as interesting as the size of the bet itself.
On October 1, SoftBank confirmed that it completed the third and final $10 billion tranche of its latest OpenAI investment.
That brings SoftBank’s cumulative investment in OpenAI to $64.6 billion — for approximately 13% ownership.
But look at the financing journey.
Back in October 2025, SoftBank sold its entire Nvidia stake — 32.1 million shares worth about $5.8 billion — as it redirected capital toward its rapidly expanding AI investments, including OpenAI. SoftBank said the sale was not a negative view on Nvidia; it was a portfolio-reallocation decision.
Then came the borrowing.
To finance this latest OpenAI commitment, SoftBank raised $11.1 billion in dollar-and euro-denominated senior notes in September.






