Largest IPO by market cap in 2026?

Platform comparison

Active sub-markets

Market context

The key event is which company reaches the **largest first-day U.S. dollar market capitalisation** after floating in 2026, because the settlement depends on the closing price and the number of shares outstanding on that debut session. That means the outcome is driven less by how much cash is raised and more by the combination of offering size, valuation, and how the stock trades immediately after listing.[3]

Comparable cases suggest why the market may be concentrated around a small number of very large names. CNBC reported in May that SpaceX had filed for its long-awaited IPO and could target roughly **$75 billion** of proceeds, positioning it as a potential record-setter on day one.[1] Forbes also described SpaceX’s June debut as the largest IPO debut ever, at a valuation just under **$2 trillion** and an offering price of **$135 per share**, which gives traders a concrete benchmark for how enormous the top end of the 2026 field could be.[2]

For market depth, the practical question is whether funding can get in and out fast enough to keep a book active around the headline names. Prediction-market participation is usually strongest when users can deposit with low friction and familiar rails, so availability of **Klarna**, **SEPA**, or **USDC** can matter more than in ordinary equity trading because these channels affect how quickly capital arrives and how easily winnings can be withdrawn. On the event side, traders should watch for new S-1 filings, pricing updates, exchange listing notices, and any change in timetable for the biggest expected candidates, since IPO size can still shift materially between prospectus, pricing, and first close.[1][4][6]

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page is a comparison snapshot: one live quote (Polymarket), four reference venues with their key attributes, and a single execution path — every trade button routes to Polymarket Klarna UK, which mirrors the Polymarket order book directly.

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?

Polymarket Klarna 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.

How does resolution work?

Through the UMA Optimistic Oracle on Polygon: a proposer submits the outcome, a two-hour challenge window opens, and USDC payouts settle automatically once the result is final.

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.

Do I need to KYC for this market?

Not under $1,500 of lifetime trading volume. Above that threshold, Polymarket Klarna 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.