Largest IPO by market cap in 2026 is a tight two-way race: Anthropic at 54%, SpaceX at 49% on $6.5M traded

Two leaders, conflicting snapshots

Anthropic stands at 54% and SpaceX at 49% in the supplied Oct 15, 2026 · 3:09 AM ET snapshot of the market for 2026’s largest IPO by market capitalization, with $6.5M traded. The accompanying summary reports no significant new platform headline in the preceding 15 minutes, making this a pricing update rather than a response to a fresh announcement.

The linked Polymarket material gives a different ranking: SpaceX at 51% and Anthropic at 43.3%, alongside xAI at 25.5%. Those figures do not match the headline snapshot. Without comparable timestamps, they cannot establish a price move or a confirmed change in leadership.

A completed listing versus a planned debut

According to Polymarket, SpaceX’s June 2026 IPO was priced at $135 per share and raised $75 billion at a $1.77–1.8 trillion valuation. That listing provides the benchmark against which the other contenders are being assessed.

Anthropic’s planned November debut carries investor valuation targets of $1.8–2 trillion and expected proceeds of up to $100 billion, according to Polymarket. The platform describes rapid revenue growth alongside substantial infrastructure spending, putting the proposed offering’s valuation range close to—and potentially above—SpaceX’s listing valuation.

Polymarket also links xAI’s 25.5% probability to its February merger into SpaceX, which placed its assets within the existing public entity rather than supporting a separate offering. Its analysis identifies AI infrastructure costs, regulatory scrutiny and post-IPO trading performance as potential influences ahead of year-end resolution, though the supplied material does not explain how those factors enter the settlement calculation.

What it means for prediction markets

• The lead depends on the snapshot. The headline favors Anthropic; the linked material favors SpaceX. The discrepancy limits conclusions about current leadership or momentum.
• The valuation comparison is close. Anthropic’s $1.8–2 trillion target range overlaps SpaceX’s reported $1.77–1.8 trillion valuation, but a planned offering is not a completed listing.
• Settlement details matter. The supplied material does not provide the precise market-cap measurement rules or explain how xAI’s merger affects its eligibility. Those gaps are important when interpreting the quoted probabilities.