Mark Zuckerberg’s fortune plunged $18 billion as shares of Meta Platforms Inc. tumbled, allowing Tesla Inc.’s Elon Musk to cement his status as the world’s third-richest billionaire.

Meta shares fell 11% Thursday in New York after the social media company said second-quarter sales were likely to come in below estimates. Zuckerberg’s one-day drop in net worth is the 11th-largest ever related to a stock move among those in the Bloomberg Billionaires Index, with his fortune now at $157 billion. Musk, 52, added $5.8 billion in wealth to $184 billion as Tesla stock continued its post-earnings rally.

The two billionaires switched ranks earlier this month, when Zuckerberg, 39, overtook Musk for the first time since 2020 following news that Tesla’s vehicle deliveries fell in the three months through March.

Shares of Menlo Park, California-based Meta dropped the most since October 2022 on Thursday after the company increased spending estimates for the year and projected second-quarter sales that were below Wall Street’s expectations, once again raising questions about whether its bets on artificial intelligence will eventually pay off for investors.

The stock is still up 25% for the year and has been trading near all-time highs for the past month, in part reflecting excitement around AI.

Shares of Austin-based Tesla surged 12% on Wednesday and another 5% on Thursday after Musk vowed to offer less-expensive vehicles as soon as this year, easing concerns about disappointing earnings results and diminished growth prospects. The stock was the worst performer on the S&P 500 Index before the rally, falling 42% through Tuesday’s close.

Musk derives his wealth primarily from his stake in the EV manufacturer, as well as his holdings in Space Exploration Technologies and X, formerly known as Twitter. Zuckerberg’s fortune is largely tied to Meta shares.

The two billionaires’ rivalry extends beyond their wealth: Musk and Zuckerberg have been engaged in an ongoing public spat that intensified when Meta launched Threads, a social-media platform that competes with Musk’s X. The two even traded barbs last year about a possible cage fight.

This article was provided by Bloomberg News.