Apple announced a partnership with OpenAI last year to integrate ChatGPT across its products. Musk responded to the announcement by threatening to ban Apple products at his companies. Grok is a rival AI offering to OpenAI’s ChatGPT and Alphabet unit Google’s Gemini, among others.

Musk called Apple’s App Store rankings an “unequivocal antitrust violation” in a post on his social-media platform X on Monday night and threatened “immediate legal action.” “Apple is behaving in a manner that makes it impossible for any AI company besides OpenAI to reach #1 in the App Store,” he said in the post.