A 44-minute call and a memo: How Alexandr Wang won Mark Zuckerberg’s trust—and a $100 billion-plus AI bet

Mark Zuckerberg once poured tens of billions of dollars into a metaverse that few people wanted to live in. Now he's spending even more on Muse , Meta's personal AI agent—the kind of assistant that, in Zuckerberg's case, coaches his MMA form between rounds and, in Alexandr Wang's, hunts down obscure loose-leaf teas from farms in Taiwan and Japan.

Those are a couple of the favorite use cases of Zuckerberg and Wang, the 29-year-old MIT dropout and Scale AI cofounder Zuckerberg tapped last year to lead Meta Superintelligence Labs. The Muse app launched in the U.S. on Sept. 8 and quickly became the most popular free app on Apple's App Store, topping 2.5 million downloads in about two weeks, according to Sensor Tower data cited by CNN . On Monday, Meta followed up with Muse Wonder , the first model from the lab that Meta calls frontier-class.

"We're going to write this check for like, I don't know, like $100 billion or $200 billion," Zuckerberg said of discussions late last year, appearing alongside Wang on the latest episode of Cheeky Pint , the podcast hosted by Stripe cofounder John Collison. "I'm like, Alex, you sure this is going to work?"

The figure was off the cuff, but the scale is real. Meta now expects 2026 capital expenditures of $130 billion to $145 billion , nearly double the $72.2 billion it spent last year—and investors have flinched at each increase.

Wang said he heard a version of Zuckerberg's question from Meta's CFO, Susan Li, at an executive gathering in Hawaii at the end of last year. "Susan pulled me aside many times," Wang said. "I just want to tell you if this doesn't work, this is going to be really, really bad. It's going to be very, very bad in financial terms. I really need to impress on you that this model has to work. It has to be good. If it's good, it's all good. We're great. But if it's bad, it's really, really, really bad."

Between sips of Guinness—a moment of apparent wincing by Zuckerberg went viral —the pair recounted how their partnership began. In April 2025, shortly after Meta's Llama 4 models landed to a lukewarm reception, Zuckerberg started reaching out for advice. ( Fortune previously reported that the two began spending more time together that month.) Wang was in a staff meeting when his phone pinged. "I got the WhatsApp notification, like, 'Have time for a call?'" Wang said. "I was like, huh, interesting."

That call ran about 44 minutes, by Zuckerberg's recollection. Two days later, Wang sent him a long memo laying out, as Zuckerberg put it, "here's what I think I would do if I were in your position."