X, the social media site formerly known as Twitter, is changing its address but staying within Elon Musk‘s corporate portfolio.

In a post on X, Musk said his artificial intelligence firm xAI acquired X in an all-stock deal valuing the platform at $45 billion, minus $12 billion in debt.

In 2022, Musk bought Twitter for $44 billion. After he dramatically overhauled its operations, shrinking its staff to a fraction of its previous size and relentlessly tinkering with its algorithm and monetization models, X lost a significant amount of value. Many of the institutional investors and private equity firms who backed Musk’s initial purchase found themselves underwater.

In a post on X announcing the deal, Musk called the social media outlet “one of the most efficient companies in the world.” He added that xAI and X’s futures “are intertwined. Today, we officially take the step to combine the data, models, compute, distribution and talent. This combination will unlock immense potential by blending xAI’s advanced AI capability and expertise with X’s massive reach. 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 view from investors in Musk’s Twitter crusade has changed significantly in recent months, since Musk emerged as a significant financial contributor to Donald Trump. After spending nearly $300 million to help get Trump elected, Musk went on to become a key advisor, overseeing an efficiency drive that has disrupted the operations of many government agencies.

In his announcement of the deal, Musk said X has more than 600 million active users. Before Musk’s ownership, as a public company Twitter reported user statistics and other metrics. In the second quarter of 2022, Twitter said it had average monetizable daily active usage (mDAU) of 237.8 million.

The transaction “will allow us to build a platform that doesn’t just reflect the world but actively accelerates human progress,” Musk wrote. “I would like to recognize the hardcore dedication of everyone at xAI and X that has brought us to this point. This is just the beginning.”