SpaceX regains lead as favorite for biggest IPO of 2026 on Polymarket

SpaceX is back on top in the race for the biggest IPO of 2026, at least according to the people putting money on it.

On October 16, Polymarket odds showed the rocket company retaking the lead as favorite for the year’s largest public debut by market cap. The trigger was a cooling in valuation expectations for its main rival, Anthropic.

A $500 billion haircut, on paper

The shift traces back to a Reuters report published on October 15. It said investors are now weighing a valuation of approximately $1.5 trillion for Anthropic’s upcoming IPO.

That is a meaningful step down. Expectations had previously been pegged at around $2 trillion.

The recalibration landed alongside Anthropic’s third-quarter financial update. The AI company reported revenue of $16.8 billion for Q3, up 45% from the $11.6 billion it posted in Q2.

Anthropic’s Q2 revenue had doubled from its Q1 figure. Going from doubling to growing 45% is still rapid expansion, but the direction of travel matters to investors pricing in years of future growth.

Anthropic’s IPO roadshow is expected to kick off the week of November 9. A potential trading date is being eyed for around late November.

The number SpaceX already put on the board

The company completed its IPO on June 12, 2026, pricing shares at $135 apiece. The offering raised approximately $75 billion.

SpaceX debuted at a valuation between $1.77 trillion and $1.8 trillion. That made it the largest IPO in history at the time.

That figure is now the bar Anthropic has to clear. At approximately $1.5 trillion, a debut at that level would leave it short of SpaceX’s opening valuation by a few hundred billion dollars.

Polymarket’s multi-outcome contract, titled “Largest IPO by market cap in 2026,” has tracked these swings in real time. As the Reuters report circulated, SpaceX’s odds climbed while Anthropic’s slid.

Earlier in the summer, Anthropic was viewed as a serious contender, with Polymarket bettors giving it an optimistic shot at overtaking SpaceX.

Why prediction markets are worth watching here

Polymarket lets users wager on the outcomes of real-world events. The prices on each outcome act as a crowd-sourced probability estimate.

The speed of this particular swing is telling. One Reuters report on October 15 was enough to flip the favorite by October 16.

What this means for the IPO market

SpaceX’s offering stands as proof that public markets can absorb a raise of approximately $75 billion.

Anthropic is still posting enormous revenue growth, and a $1.5 trillion valuation would rank among the largest debuts ever.

The key dates to watch are clear. Anthropic’s roadshow is expected to begin the week of November 9, and that is where institutional demand will be tested directly.