Meta's big AI gamble just cost Mark Zuckerberg two spots on the billionaire's index

• Mark Zuckerberg lost about $29.2 billion overnight as Meta's stock fell after its earnings report.
• The drop pushed him two spots lower on Bloomberg's Billionaires Index to fifth place.
• The Meta CEO fielded a flurry of investor questions about the company's AI spending during a call on Wednesday.

Mark Zuckerberg's net worth just took a tumble.

The Meta CEO dropped two spots on Bloomberg's Billionaires Index after the company's quarterly earnings report sent its stock sliding. Zuckerberg lost around $29.2 billion overnight, leaving him with $235 billion.

The drop pushed him to fifth place on the index, below Amazon's Jeff Bezos and Alphabet's Larry Page.

Page's net worth increased to $244 billion as Alphabet's shares rose 2.5% after the company beat earnings estimates, buoyed by robust growth in Google Cloud and Search.

Bezos' fortune fell by about $6.6 billion. Meanwhile, Amazon's stock jumped more than 13% on Thursday after the company reported huge growth in the third quarter, including in its cloud business, Amazon Web Services.

Zuckerberg's fortune has taken hits in the past when earnings spooked its investors. Meta shares plunged about 24% in 2022 after the company missed earnings targets and Zuckerberg pledged to pour billions more into building the metaverse. The metaverse bet wiped out about $100 billion from his wealth at that time.

Investors have been jittery about Meta's big AI spending plans. Meta said on Wednesday it could spend $70 billion to $72 billion on AI capital expenditures in 2025, up from its previous guidance of $66 billion to $72 billion. Meta CFO Susan Li said spending will climb even higher in 2026 as Meta invests in data centers, cloud services, and salaries for the growing ranks of AI researchers and engineers hired for Meta Superintelligence Labs.

Mark Zuckerberg faced a flurry of questions in a call with analysts on Wednesday about how Meta is spending the billions it's pouring into AI.

When JPMorgan analyst Doug Anmuth asked about Meta's soaring costs, Zuckerberg said pouring money into AI was the smart play, even if the company ends up overshooting.

In what he called the "very worst case," Meta would have "pre-built for a couple of years," taking on some depreciation costs before eventually growing into the extra capacity, Zuckerberg said.

That was better than being caught short on compute when the next wave of AI breakthroughs arrives, he added.

After the earnings report was released, Meta's stock plummeted nearly 9%.

As of Thursday evening, Meta's stock had fallen more than 11%.

Zuckerberg did not respond to a request for comment from Business Insider.

Investors on edge about AI spending

Microsoft's stock prices also dropped on Wednesday following its earnings announcement. The software giant reported a record $34.9 billion in capital expenditures last quarter, up from the $24.2 billion the quarter before. The company also said spending could increase in 2026.

Shares of Microsoft fell 3% at intraday lows on Thursday.

Peter Berezin, chief market strategist at BCA Research, said the stock declines in Meta and Microsoft were a "yellow flag" for the AI trade. In a recent note to clients, he said a possible warning for the AI trade could be when a major tech firm announces plans to spend more on capex, only to see their stock prices fall.

Berezin told Business Insider on Thursday that he expected to see that play out across the sector in the future, which would mark a clearer warning that the AI hype is starting to deflate.

"When Zuck comes out and says, we're making all these investments based on the best-case scenario for AI because we don't want to be left behind — that's dangerous, right? Because if you don't get that best-case scenario, you are going to have pretty significant write-offs," Berezin said.