Elon Musk said on Friday that he had sold X, his social media company, to xAI, the artificial intelligence start-up he founded in 2023, in an unusual arrangement that may raise conflict-of-interest questions.

The all-stock deal valued xAI at $80 billion and X at $30 billion, Mr. Musk said on X. The price for X is a $14 billion discount from the $44 billion that Mr. Musk paid for the social media company in 2022. Both companies are privately held.

“XAI and X’s futures are intertwined. Today, we officially take the step to combine the data, models, compute, distribution and talent,” Mr. Musk wrote in his post. “The combined company will deliver smarter, more meaningful experiences to billions of people while staying true to our core mission of seeking truth and advancing knowledge.”

The two Musk companies already share significant resources. The artificial intelligence models of xAI are trained on data posted by X users, the companies share some engineers and xAI’s chatbot, Grok, was available to paying X subscribers. Last month, bankers for X told investors that some of the social media’s revenue came from xAI.

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