The investment forms part of SoftBank’s plan to invest up to $40.0 billion in the artificial intelligence major, a commitment first disclosed on March 31, 2025.

“With this transaction, the Company has fully satisfied its commitment to invest in OpenAI under its March 2025 agreement, alongside the participation of third-party co-investors,” SoftBank said in a statement.

Following the latest investment, SoftBank’s aggregate ownership interest in OpenAI now stands at approximately 11%.

The Japanese conglomerate had completed the first closing in April 2025, investing $7.5 billion through SoftBank Vision Fund 2 (SVF2). The second closing involved an additional $22.5 billion, also routed through SVF2.

In addition, third-party co-investors contributed an oversubscribed and upsized $11.0 billion, taking the final aggregate funding to $41.0 billion, which has now been fully funded.

Commenting on the investment, Masayoshi Son, Chairman and CEO of SoftBank Group Corp., said, “We are deeply aligned with OpenAI’s vision of ensuring artificial general intelligence benefits all of humanity.”

Sam Altman, CEO of OpenAI, said SoftBank recognised the potential of artificial intelligence early.

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