SoftBank is in talks to invest up to $25 billion into ChatGPT owner OpenAI and become the AI firm’s largest financial backer, the Financial Times reported on Wednesday, as the Japanese conglomerate continues to expand into the sector.

SoftBank could invest $15 billion to $25 billion directly into Microsoft-backed OpenAI, apart from its $15 billion commitment to Stargate, the report said, citing sources.

Stargate is a joint venture by Oracle, OpenAI and Softbank, that plans to invest $500 billion to help the United States stay ahead of China and other rivals in the global AI race.

The venture was announced by U.S. President Donald Trump, SoftBank CEO Masayoshi Son, OpenAI CEO Sam Altman and Oracle Chairman Larry Ellison at the White House last week.

However, since then, a little-known startup from China, DeepSeek has upended markets with a free artificial intelligence assistant it said was developed cheaply using lower-cost chips and less data than U.S. rivals.

OpenAI, SoftBank each commit $19bn to Stargate AI data center, the Information reports

SoftBank has fallen more than 12% since the selloff began.

SoftBank CEO Son’s plan to take a large stake in OpenAI and meet its Stargate commitments has been vetted by senior executives and the board at OpenAI, the newspaper reported. Last year, SoftBank took a $1.5 billion stake in OpenAI.

OpenAI was valued at $157 billion in its last funding round, cementing its status as one of the most valuable private companies in the world.

OpenAI and SoftBank did not immediately respond to Reuters’ requests for comment.