Billionaire Elon Musk has just become the first person in world history to have a net worth of $800 billion or more after his SpaceX company acquired the artificial intelligence and social networking company xAI.

Forbes estimates that this deal increased Musk’s net worth by $84 billion, bringing it to a record high of $852 billion.

Prior to the deal, billionaire Musk owned approximately 42% of SpaceX, valued at $336 billion, based on a December share offering that valued the privately held rocket company at $800 billion. He also held approximately 49% of xAI, valued at $122 billion, according to a private funding round earlier this month that valued the company at $250 billion.

Following the merger, with SpaceX valued at $1 trillion and xAI at $250 billion, Forbes estimates that Musk now holds 43% of the combined company, worth $542 billion.

That makes SpaceX Musk’s most valuable asset. He also owns a 12% stake in Tesla worth $178 billion and Tesla stock options worth an additional $124 billion.

This figure does not include the record compensation package approved by Tesla shareholders in November, which could give Musk up to $1 trillion in additional stock if Tesla achieves “Mars-like” performance milestones, such as increasing its market capitalization more than eightfold in the next 10 years.

This is the second time in less than a year that two of Musk’s companies have merged. Last March, the billionaire announced the merger of his AI company xAI with his social media company X (formerly Twitter) in a deal valuing xAI at $80 billion and X at $33 billion (almost the amount he paid to buy Twitter in 2022, not including debt).

Musk’s dual role as both buyer and seller in these deals has raised some questions about the valuations he sets.

Billionaire Musk has reached four major wealth milestones in just four months. He became the first person to possess $500 billion in October 2025 as Tesla stock surged after he left President Donald Trump’s Department of Government Performance (DOGE) to focus on his electric car company.

On December 15, 2025, Musk became the first person to reach $600 billion after private investors valued SpaceX at $800 billion, up from $400 billion in August.

Four days later, he became the first person to reach $700 billion after the Delaware Supreme Court reinstated his Tesla stock options, which had been overturned by a lower court in 2024.

Currently, Musk is $578 billion richer than the world’s second-richest person, Google co-founder Larry Page, whose net worth is estimated at $281 billion. He is just $150 billion short of becoming the first person in the world to reach $1 trillion in assets.