The $41 Billion Bet: Why SoftBank Sold Nvidia to Buy OpenAI

SoftBank Group has officially wired the final tranche of a $41 billion investment into OpenAI, securing an 11% stake in the world’s most valuable startup. This isn't just a funding round; it is a liquidation event. To make this deal happen, SoftBank CEO Masayoshi Son sold his entire $5.8 billion stake in Nvidia, the very company powering the AI boom, to double down on the software company attempting to transcend it.

The Great Rotation

The scale of this capital injection is unprecedented in private equity history. The final transfer of $22.5 billion, completed late last week, finalizes a deal structured back in March 2025. At that time, the entry valuation was locked in at $300 billion, a figure that now looks like a discount compared to recent secondary market valuations hitting $500 billion.

Masayoshi Son is effectively betting that the model is more valuable than the silicon. By exiting Nvidia and offloading nearly $5 billion in T-Mobile US shares, Son has pivoted SoftBank’s entire strategy from a diversified "cluster of No. 1s" to a singular, existential bet on Sam Altman.

"We are deeply aligned with OpenAI's vision of ensuring AGI benefits all of humanity," Son stated in the official announcement. It is a polite corporate pleasantry that masks a ruthless financial maneuver: SoftBank is now the largest external shareholder in OpenAI after Microsoft.

Project Stargate: The $500 Billion Endgame

The $41 billion isn't just for operational burn; it is the down payment on Project Stargate. This is the code name for a massive AI infrastructure initiative involving OpenAI, SoftBank, and Oracle. The goal is to build a distributed "AI grid" capable of training the next generation of models.

This infrastructure push is aggressive and deliberate. Just recently, SoftBank signaled its intent by betting $4 billion on DigitalBridge to fuel its artificial super-intelligence obsession, securing the physical data centers required to keep the lights on. While Microsoft controls the Azure cloud layer, SoftBank is positioning itself as the financier of the physical layer.

"SoftBank saw the potential of AI early and committed with a deep belief in its impact on humanity," said OpenAI CEO Sam Altman. "Their global leadership and scale help us move faster and bring advanced intelligence to the world."

The partnership with Oracle is critical here. While SoftBank brings the cash, Oracle provides the data center capacity that OpenAI is desperate for, as it attempts to lessen its reliance on Microsoft's Azure infrastructure.

The Valuation Gap

For SoftBank, the math is aggressive but simple. They bought in at a $300 billion valuation. With secondary markets already trading OpenAI shares at $500 billion, Son is sitting on a massive paper profit before the ink is even dry.

However, this paper wealth is contingent on a liquidity event. OpenAI recently restructured into a Public Benefit Corporation (PBC), a move SoftBank reportedly demanded to clear the path for a potential IPO. If OpenAI goes public in late 2026 or 2027 as rumored, SoftBank’s $41 billion could easily double. If the AI bubble bursts, Son has sold the only profitable chip company in history to buy a bag of depreciating software.

Masayoshi Son has a history of spectacular wins (Alibaba) and catastrophic losses (WeWork). This deal is his final attempt to correct the record. By selling Nvidia to buy OpenAI, he is betting that in the long run, intelligence will be a scarce resource, while GPU compute will become a commodity. For the next six months, watch for the announcement of the first "Stargate" facility, if they break ground before June, the bet is working.