Sam Altman, chief executive officer of OpenAI Inc., left, and Tim Cook, chief executive officer of Apple Inc., during a dinner with tech leaders in the State Dining Room of the White House in Washington, DC, US, on Thursday, Sept. 4, 2025. US President Donald Trump said he would be imposing tariffs on semiconductor imports "very shortly" but spare goods from companies like Apple Inc. that have pledged to boost their US investments. Photographer: Will Oliver/EPA/Bloomberg via Getty Images

Apple on Friday sued OpenAI in federal court in Northern California, alleging trade secret theft, saying that the artificial intelligence lab took the iPhone maker's intellectual property in order to develop its own consumer hardware.

"This much is clear, however: at every level, from members of its Technical Staff to its Chief Hardware Officer, and in coordination with business partners, OpenAI has been stealing Apple's trade secrets and confidential information," the company said in a legal filing.

It's a shocking reversal for the two companies, which entered into a high-profile partnership in 2024, when ChatGPT was integrated into the iPhone's operating system. OpenAI CEO Sam Altman visited Apple's headquarters for the announcement.

But relations between the two companies have chilled since OpenAI announced plans to enter the hardware industry last year, when it bought former Apple designer Jony Ive's startup, called IO Products, for $6.4 billion.

Apple's updated version of its Siri assistant, which is coming out this fall, is based on Google 's Gemini AI models instead of OpenAI's technology.

Most of Apple's allegations involve former employees who have interviewed with or joined OpenAI.