Mark Zuckerberg’s fortune fell by nearly $20 billion in two trading sessions as Meta shares slid. Forbes’ real-time billionaires tracker showed an $8.9 billion drop on Friday, September 25, followed by another $10.9 billion fall on Monday, taking his net worth to $246.7 billion and below the $250 billion mark.

Meta shares dropped about 4 percent on Friday after a 4.5 percent gain on Thursday. The stock had climbed roughly 36 percent in September, pushing toward a $2 trillion market cap on enthusiasm for the company’s Muse AI assistant. Sensor Tower data via Forbes put Muse downloads at 2.8 million in its first two weeks.

Goldman Sachs warned that AI hyperscalers including Meta, Microsoft, Alphabet, Amazon and Oracle need about $300 billion in annual AI-services revenue to break even on capital spending, and about $1 trillion for meaningful profits.

Zuckerberg, who owns about 13 percent of Meta, slipped from fourth to sixth on the Forbes billionaire list. The slide reflects investor unease about whether massive AI investments can deliver returns fast enough to justify current valuations.