OpenAI has ended its partnership with Cursor, the AI coding editor, after Elon Musk's SpaceX acquired the company, choosing to sacrifice significant revenue rather than continue supplying its models to a Musk-controlled business. The move highlights the depth of OpenAI's distrust of Musk, with the firm citing past instances of "Elon Musk's companies violating contracts" and concerns that SpaceX could misuse its technology, including possibly using OpenAI's models to help train Musk's rival AI venture, xAI.

Cursor had been one of OpenAI's top five customers by revenue at the start of 2026, and by spring OpenAI estimated the partnership could generate over $1 billion in annualised revenue. OpenAI, which reportedly now earns more than $40 billion annually across subscriptions, advertising and its Codex coding tool, is seeking to present a stable business ahead of a planned stock market listing next year. Cursor chief executive Michael Truell, who now also leads teams at SpaceX, pushed back publicly, claiming OpenAI's models made up only about 5% of Cursor's user traffic, a figure OpenAI's product chief disputed as not reflecting actual value or revenue. The split follows a long history between the firms, including OpenAI's early investment in Cursor's 2023 seed round and a reported prior acquisition approach.