Elon Musk has threatened to take legal action against Apple on behalf of the AI startup Xai, alleging that the iPhone manufacturer is favoring OpenAI and breaching antitrust laws regarding App Store rankings. This statement drew a sharp response from OpenAI CEO Sam Altman and ignited a feud between the two former business associates at X.

“Apple is operating in a manner that prevents non-OpenAI AI companies from achieving the top position on the App Store. This clearly violates antitrust regulations. Xai is prepared to take swift legal measures,” Musk declared in a post on X.

In another post that day, he stated:

Currently, OpenAI’s ChatGPT occupies the top spot in the “Top Free Apps” category of the US App Store, while Xai’s Grok sits in fifth place. Apple has partnered with OpenAI to integrate ChatGPT across iPhone, iPad, and Mac. Neither Apple nor Xai provided any comments.

Altman replied to Musk on X, saying, “This is an unexpected claim considering we’ve heard Elon is attempting to manipulate X for his own benefit and to undermine his competitors, including those he dislikes.” Reports indicate that Musk has tweaked X’s algorithm to favor his own posts.

Altman and Musk co-founded OpenAI in 2015, but Musk departed the startup in 2018 and withdrew his funding after proposing they take control. Musk has since filed two times for a planned shift to commercial entities, alleging “Shakespeare’s proportional deception ceit.” Altman has characterized Musk as a bitter and envious ex-partner, resentful of the company’s achievements post-departure.

Musk responded to Altman’s tweet, stating, “You got 3 million views for dishonest posts. You’re a liar; despite having 50 times your followers, my engagement has far exceeded yours!”

Altman retorted to Musk several times, initially calling the lack of views a “skill issue” or “bot-related” before posing legal questions.

Users on X highlighted through the Community Notes feature that several apps, aside from OpenAI, have claimed top positions on the App Store this year.

For instance, the Chinese AI app Deepseek reached the No. 1 position in January, while Perplexity ranked first in the App Store in India in July.

One user inquired about Grok, X’s native AI. The chatbot replied: “Based on confirmed evidence, Sam Altman is correct.”

Musk’s remarks come as regulators and competitors heighten their scrutiny of Apple’s App Store dominance.

Earlier this year, an EU antitrust regulator ordered Apple to pay a fine of 500 million euros ($581.15 million).

In early 2024, the U.S. Department of Justice filed an antitrust lawsuit against Apple, accusing the iPhone manufacturer of establishing and maintaining “broad, persistent, and illegal” monopolies in the smartphone market.