SoftBank is reportedly finalizing a US$40 billion investment in OpenAI, valuing the company at US$260 billion before the funding, according to sources cited by CNBC.

The investment, set to be distributed over 12 to 24 months, could raise OpenAI’s post-money valuation to US$300 billion.

SoftBank may also syndicate up to US$10 billion of the total amount, making it OpenAI’s largest backer, surpassing Microsoft.

This latest funding follows SoftBank’s US$3 billion annual commitment to integrating OpenAI’s technology across its subsidiaries, including chip manufacturer Arm.

Part of the investment is expected to support Stargate, a joint venture by SoftBank, OpenAI, and Oracle to enhance US AI infrastructure.