SpaceX Retakes Polymarket Lead for 2026's Biggest IPO After Report Anthropic Valuation Talk Fell to $1.5 Trillion

A prediction market just moved on one news report. That is the whole story so far, and the real test comes next month.

On Oct. 16, Polymarket odds put SpaceX back in front in the contract titled "Largest IPO by market cap in 2026." The swing followed a Reuters report on Oct. 15 that investors are now weighing a valuation of about $1.5 trillion for Anthropic's upcoming offering. Expectations had previously sat near $2 trillion.

Polymarket lets users wager on real-world outcomes. The contract prices work as a crowd-sourced probability, not a forecast from anyone with inside knowledge of either company's books.

Anthropic's numbers

The valuation talk landed alongside Anthropic's third-quarter update. Revenue came in at $16.8 billion, up 45% from $11.6 billion in the second quarter.

That is fast growth by any normal standard. It is also a sharp slowdown: second-quarter revenue had doubled from the first quarter.

Anthropic has not yet gone public. Its roadshow is expected to begin the week of Nov. 9, with a trading date being eyed for around late November. Both are expected dates, not scheduled events, and the $1.5 trillion figure is what investors are weighing, not a set price.

SpaceX is the bar

SpaceX went public in June at $135 a share under the ticker SPCX. The Motley Fool reports the offering raised more than $85 billion after the overallotment option was exercised, the largest IPO ever. Crypto Briefing put the debut valuation between $1.77 trillion and $1.8 trillion.

On those numbers, an Anthropic debut at about $1.5 trillion would land a few hundred billion dollars short of SpaceX's opening valuation. To win the Polymarket contract, Anthropic would need to price or trade well above what investors are now discussing.

SpaceX's stock has not been a straight line. Shares climbed about 50% to a peak within days of the listing, then drifted back. The Motley Fool's analysis has the stock trading roughly 15% above the IPO price about four months in, and at times below it.

What SpaceX investors are buying

SpaceX runs three businesses: space, satellite connectivity and artificial intelligence. Starlink is the biggest revenue driver. Subscribers doubled and that unit's revenue climbed 65%, per the Motley Fool's account of the latest quarter.

The AI unit is the drag. AI capital spending hit $15 billion in the recent quarter, against about $7 billion in revenue for the entire company.

Starship recently completed its 14th flight, putting 26 Starlink satellites into orbit. SpaceX has also named space-based data centers as a goal.

One wrinkle: Anthropic and Google have both signed deals with SpaceX to access compute. The company Polymarket bettors treat as its chief IPO rival is also a customer of the SpaceX AI business.

The case against reading too much into the swing

Nothing in the reporting says Anthropic's business is weakening in absolute terms. Crypto Briefing itself notes the company is still posting enormous revenue growth, and a $1.5 trillion valuation would rank among the largest public debuts ever.

The odds flip also reflects a narrow slice of bettors reacting to one wire report. The move from Oct. 15 to Oct. 16 shows how fast sentiment can turn, not that the outcome is decided. Earlier in the summer, bettors gave Anthropic a real shot at overtaking SpaceX.

There is also the valuation itself. Roadshows exist to test demand. Bankers can price above the range investors are floating if orders come in heavy, and Reuters' number is a snapshot of discussion weeks before books open.

What comes next

The next fixed marker is the roadshow, expected the week of Nov. 9. Anthropic has not publicly confirmed a price range in the reporting to date. Once it does, the gap between its target and SpaceX's $1.77 trillion to $1.8 trillion debut will be a hard number, not a betting line.

It remains to be seen whether demand from the roadshow pushes the final valuation back toward the $2 trillion that investors were discussing before Oct. 15.