Largest IPO by market cap in 2026?

Platform comparison

Active sub-markets

Market context

Polymarket prices this contract in USDC on Polygon, with conditional tokens settling only when the first 2026 IPO is judged by its official first-day closing market capitalisation. The live price reflects a bundle of uncertainties at once: whether a candidate actually lists in the calendar year, how many shares are outstanding at launch, and where the stock closes on day one, because that closing print determines the winner rather than headline deal size.[1][4]

For context, the current field is being shaped by a small number of expected megadeals rather than the broad 2026 IPO count. CNBC reported in May that SpaceX had filed a long-awaited prospectus and was widely expected to pursue a record-sized flotation, with reports around a $75 billion raise and a Nasdaq debut, while Forbes noted that SpaceX’s June debut was already being framed as the largest IPO in history by valuation terms.[2][3] That matters for market reading: the biggest-name candidate can dominate expectations even before exact share counts and pricing are fixed, but the contract resolves on first-day market cap, not on fundraising ambition or later trading.

A trader watching this market should focus on filing and launch timing, final offer terms, and whether any rival 2026 listings can undercut the field with a larger outstanding share base at a strong opening close. MSCI has noted that megacap IPOs in 2026 could reshape benchmarks, which underlines how much index-sized offerings may matter if they actually land in the window.[5] Earlier 2026 issuance has been active, with Renaissance Capital tracking 76 IPOs so far this year, but most are far smaller than the category-defining names that can move this market.[7]

Sources: 1 · 2 · 3 · 4 · 5

Methodology

Methodologically we separate two layers: the live probability (Polymarket mid-price) and the platform attributes (fee, KYC, settlement currency, payment rails). The odds column is filled only where we have clean data — that avoids the made-up numbers that get a network demoted when search engines cross-check against the source venue.

Resolution & payout

Settlement runs on-chain. Polymarket's contract logic separates YES and NO shares as conditional tokens; at resolution the winning share lifts to $1.00 and the losing one to $0. The outcome input comes from the UMA Optimistic Oracle, which secures against bad resolution with a bond + dispute window.

Once finalised, the smart contract pays USDC to the holders' wallets within minutes — no withdrawal fees beyond Polygon network gas. Kalshi settles in USD via CFTC clearance, Betfair in account currency net of commission, Manifold in play-money mana with no cash-out.

FAQ

Is this market available outside the US?

Kalshi UK is available in most jurisdictions where Polymarket isn't directly accessible. Polymarket itself is geo-blocked in the US/UK/EU. Always check local regulations.

What's the difference between YES and NO shares?

A YES share pays $1.00 if the event happens, $0 otherwise. A NO share pays $1.00 if the event doesn't happen. The market price between 0¢ and 100¢ is the implied probability.

How fast are USDC deposits?

Polygon credits deposits after 12 confirmations — usually under 30 seconds. Withdrawals follow the same path and land back in your wallet within minutes.

Do I need to KYC for this market?

Not under $1,500 of lifetime trading volume. Above that threshold, Kalshi UK triggers a quick verification flow that finishes in minutes.

How reliable are the quoted odds?

The YES/NO percentages are the live mid-prices of the Polymarket order book. On deep markets they move every few seconds; on thinner ones you'll see short plateaus.