Meta's Muse Adds $192 Billion in Market Cap in One Day

Meta (META) added $192 billion to its market cap on Monday as investors bet that the company's new Muse AI agent can crack the enterprise market. The stock gained 11.3% to close at $741.25 and rose another 1.5% on Tuesday, lifting CEO Mark Zuckerberg's net worth by more than $13 billion.

The catalyst was raw adoption data. Muse hit 2.8 million downloads in its first 12 days across the US and Canada app stores, according to Sensor Tower, surpassing ChatGPT's early trajectory — 1.8 million downloads versus 1.3 million for ChatGPT over the same window. Muse also climbed to the top spot on Apple's App Store and set a new US daily download record of 264,000 on Sept. 19, its third straight day above 200,000.

"Lots can and will change in the future, but the key, simple point is that Meta has a hit on its hands with Muse," Evercore ISI analyst Mark Mahaney wrote in a new note.

"Muse's goal was to make AI accessible to way more people," Meta chief AI officer Alexandr Wang said in an X post.

The Enterprise Question

The most important factor driving the stock, according to Mahaney, is Muse's potential to unlock unforeseen profits. If the agent can break into the lucrative enterprise market during the AI infrastructure boom, the revenue opportunity would be significant for a company that Wall Street has long treated as a consumer-only story.

Mahaney laid out his reasoning in the note. He argued the market has fixated on enterprise AI at the expense of consumer products. "The market has been hyper-focused on the Enterprise AI market. Excessively focused, we believe," he wrote. "We get it. Enterprises pay for productivity. Consumers don't. Or at least that's what the market assumes."

He pointed to two competitors as evidence of that bias. Anthropic has eschewed the consumer AI market, directly criticizing one of the biggest consumer monetization methods — advertising — via Super Bowl TV ads. "(There's deep irony in that last sentence.)," Mahaney noted. OpenAI, for its part, has touted its goal of being primarily enterprise revenue driven by the end of 2026.

That enterprise obsession has cost Meta. The market has largely awarded the company the lowest P/E multiple of what Mahaney calls the "Hyperscaler Crew" because its substantial AI investments were not clearly linked to an enterprise opportunity like cloud computing. Muse changes that calculation.

Three Reasons Muse Matters

Mahaney gave three reasons the product matters to Meta shareholders.

First, Muse is a tangible sign of successful product innovation and ROAI — evidence that Meta's substantial AI investments, which he pegs at more than $200 billion in annualized capex and opex, have not been in vain.

Second, Muse suggests "a potentially very dramatic new driver of usage and engagement for Meta," according to the analyst.

Third, the agent carries substantial new monetization opportunities in the form of advertising, subscriptions, and transaction revenue share, set against what Mahaney describes as multi-trillion dollar total addressable markets.

What Comes Next

The bet now rests on conversion. Muse's download numbers beat ChatGPT's early pace, and the stock has already repriced Meta by nearly $200 billion in a single session. The open question — one Mahaney himself flags with "lots can and will change" — is whether that consumer momentum translates into the enterprise revenue and monetization streams that would justify a re-rating of the stock. If it does, Meta enters the enterprise AI conversation with a distribution engine its rivals lack.