Mark Zuckerberg's wealth may slide $25 billion in a day as Big Tech faces $350 billion sell-off

• Mark Zuckerberg's net worth could shrink by $25 billion on Thursday.
• Meta's stock plunged 15% in premarket trading on Thursday as investors balked at its earnings.
• Amazon, Alphabet, and Microsoft shares also fell, raising the prospect of a Big Tech sell-off.

Mark Zuckerberg's fortune could shrink by $25 billion in a single day due to Meta's post-earnings slump.

The cofounder and CEO of Facebook, Instagram, and WhatsApp's parent company was worth an estimated $175 billion at Wednesday's close, per the Bloomberg Billionaires Index.

Zuckerberg has a stake of about 13% in Meta that was valued at around $170 billion at Wednesday's close. However, the stock price tumbled as much as 15% to $420 in premarket trading on Thursday, indicating Zuckerberg's shares are now worth $25 billion less at $145 billion.

If that decline persists after the market open, Zuckerberg's net worth could plunge to under $150 billion. That would rank him in fifth place on Bloomberg's rich list, below Microsoft cofounder Bill Gates, assuming Gates' wealth doesn't drop significantly too.

A $25 billion reduction in wealth in one day would be remarkable, as only the top 70 richest people in the world command fortunes of that size.

Moreover, Zuckerberg's net worth was up $47 billion this year prior to Wednesday's close, making him the biggest wealth gainer on the list by far.

He even overtook Elon Musk a few days ago, largely thanks to Tesla's ongoing troubles. But Musk has regained third place thanks to a post-earnings bump in Tesla's stock price.

Zuckerberg seemed eager to reassure shareholders about Meta's sliding stock price during the company's earnings call on Wednesday. Yet he also made clear that it wouldn't deter him from investing heavily in artificial intelligence.

'Long-term investment'

"We've historically seen a lot of volatility in our stock during this phase of our product playbook, where we're investing and scaling a new product, but aren't yet monetizing it," he said. "We saw this with Reels, Stories, as News Feed transitioned to mobile and more."

"Historically investing to build these new scaled experiences in our apps has been a very good long-term investment for us and for investors who have stuck with us and the initial signs are quite positive here too," he continued. "But building a leading AI will also be a larger undertaking than the other experiences we've added to our apps and this is likely going to take several years."

Meta wasn't the only Big Tech stock under pressure, signaling investors may be souring on AI, or worrying about market headwinds such as foreign conflicts, stubborn inflation, a potential recession, and interest rates perhaps staying higher for longer.

The Facebook owner was poised to shed over $180 billion of market value on Thursday. Amazon, Alphabet, and Microsoft shares also slid before the bell, raising the prospect that some $170 billion in market value could be lost between the three of them, and more than $350 billion including Meta.