SoftBank has completed payment for its share of the largest private funding round on record. On October 1, 2026, the Japanese company closed the third and final tranche of its $30 billion follow-on commitment to OpenAI, injecting an additional $10 billion.

The payment raises SoftBank's cumulative investment in OpenAI to $64.6 billion and leaves the firm holding an approximate 13% ownership stake in the ChatGPT developer.

A social media post circulating on X claimed that Nvidia and SoftBank had each put $10 billion into OpenAI. The SoftBank portion is accurate. Nvidia's involvement is different: the chipmaker contributed $30 billion to the February 2026 round but did not finalize an additional $10 billion tranche in October, despite earlier speculation that it would.

The Round, Tranche by Tranche

In late February 2026, OpenAI raised between $110 billion and $122 billion at a pre-money valuation of approximately $730 billion. With the new capital included, the post-money valuation reached roughly $840 billion to $852 billion. Tranching — splitting a single commitment into multiple staged payments — is a structure used in some exceptionally large private rounds, and the SoftBank follow-on is a clear example of it in practice.

Three backers accounted for most of the total. Amazon committed $50 billion, with portions of that amount contingent on OpenAI reaching specified milestones, while Nvidia and SoftBank each injected $30 billion. Milestone-gated capital like Amazon's means the headline round total the cash OpenAI has actually received are not the same number — a distinction worth keeping in mind when comparing reported round sizes.

SoftBank structured its $30 billion follow-on commitment in three installments rather than a single lump sum. The October 1 payment was the last of those tranches, at $10 billion. With the final installment closed, SoftBank's total exposure to OpenAI stands at $64.6 billion.

Use of Proceeds

OpenAI has directed the funding toward expanding its compute and data center capabilities. Compute and data center capacity is what allows AI developers to train new models and serve existing ones, and it is typically the most capital-intensive part of building frontier AI systems — which is why funding at this scale flows there. Amazon's milestone-based structure means not all of its $50 billion arrives automatically, so a portion of the headline figure depends on OpenAI delivering on agreed targets.

What It Means

For SoftBank, the completed commitment cements one of the most concentrated bets in its portfolio. An approximate 13% stake in a company valued between $840 billion and $852 billion post-money ties a meaningful share of the firm's fortunes to OpenAI's performance. As a sizable minority position, its value moves directly with OpenAI's valuation in any future fundraising.

For Nvidia, its $30 billion contribution to the February round stands as its finalized commitment, and no additional $10 billion tranche closed in October.

For Amazon, the open question is how much of its $50 billion ultimately flows, given that portions depend on milestones being met.

Several developments are worth monitoring from here. The first is whether Amazon's milestone-linked funding is released in full. The second is how quickly OpenAI's new compute and data center capacity comes online. The third is whether the post-money valuation of roughly $840 billion to $852 billion holds in any future fundraising.