Platform comparison
| Platform | YES odds | NO odds | Fee | KYC | Settlement | |
|---|---|---|---|---|---|---|
Polymarket (via Polymarket Alternative UK) Pick polygram.ink (preferred broker) |
20% | 80% | 0% (USDC on-chain) | No-KYC up to $1,500 | USDC, auto via UMA oracle | View on Polymarket → |
Polymarket (direct) polymarket.com |
20% | 80% | 0% | Geo-blocked in US/UK/EU | USDC, on-chain | View on Polymarket → |
Kalshi kalshi.com |
— | — | Up to 7% per trade | US-only, KYC required | USD | View on Polymarket → |
Betfair Exchange betfair.com |
— | — | 2-5% commission | Full KYC from first trade | GBP / EUR | View on Polymarket → |
Manifold Markets manifold.markets |
— | — | Play-money (mana) | None — play-money | Mana (no cash-out) | View on Polymarket → |
Outcome probabilities
Current market-implied probability for each outcome, from the live order book.
| Outcome | Probability |
|---|---|
| December 31, 2026 | 20% |
| September 30, 2026 | 2% |
| August 31, 2026 | 0% |
| July 31, 2026 | 0% |
| December 31, 2025 | 0% |
| June 30, 2026 | 0% |
Market context
Polymarket is pricing **OpenAI going public by the deadline at just 1% yes**, which on-chain means the market is currently assigning only a tiny chance that the conditional tokens tied to this event will settle in the affirmative. On Polymarket, buyers and sellers post **USDC** on **Polygon**, and the contract resolves from a consensus of credible reporting rather than a single filing, so the key question is not whether OpenAI has IPO optionality but whether it actually completes a first public share sale before the window closes.
That low probability sits against a timeline that has already slipped. Reuters reported in June that OpenAI had confidentially filed for a US IPO, but also that the company had not fixed timing and was increasingly being viewed as a 2027 story rather than a 2026 one.[15][3] CNBC likewise reported that traders on another prediction venue were leaning towards an early-2027 announcement rather than a near-term debut.[1] For context, comparable late-stage tech listings often spend months in confidential filing, public S-1, roadshow, pricing and exchange steps before first trade; until those milestones are visible, markets usually discount the odds of a completed IPO materially.
A trader watching this contract should focus on three catalysts: a public S-1, an official timetable or roadshow launch, and any reporting on whether the company is leaning into 2026 or pushing to 2027.[6][15][7] Reuters has noted that OpenAI’s advisers and leadership have floated both an earlier debut and a later one, which matters because the market settles on completion, not aspiration.[3][5] Any credible report of a signed underwriting calendar, pricing range, or exchange listing would be the clearest repricing trigger; absent that, the 1% implied probability is consistent with a very high bar for completion before year-end.
Methodology
This page is a comparison snapshot: one live quote, four reference venues with their key attributes, and a single execution path — every trade button routes to Polymarket Alternative UK, which mirrors the Polymarket order book directly.
Resolution & payout
Polymarket-based markets settle through the UMA Optimistic Oracle on Polygon. A proposer submits the outcome, a two-hour challenge window opens, and unchallenged proposals finalise the resolution. Payouts settle automatically in USDC the moment the result is final — no bookmaker, no delay.
Kalshi-based markets settle in USD via the CFTC-regulated clearinghouse. Betfair Exchange settles in GBP/EUR net of commission. Manifold is play-money and does not pay out real funds.
UK Frequently Asked Questions
- Where can I trade this market with the lowest fees?
- Polymarket is geo-blocked in the US/UK/EU. The easiest 0%-fee broker into the same order book is Polymarket Alternative UK. Kalshi charges up to 7% per trade; Betfair Exchange takes 2-5% commission on net winnings.
- 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.
- Is Polymarket legal in the UK?
- Polymarket is accessible to UK traders but is not UKGC-licensed. It operates under US CFTC jurisdiction. UK residents face no domestic legal prohibition on using it, but UKGC consumer protections do not apply. For UKGC-regulated alternatives, Betfair Exchange and Smarkets offer similar prediction-style markets.
- Do I pay tax on prediction market profits in the UK?
- UKGC-licensed platform profits (Betfair, Smarkets) are typically tax-free gambling winnings for UK individuals. Polymarket profits involve USDC crypto transactions, which HMRC treats as Capital Gains Tax events. Keep full transaction records and report via Self Assessment if gains exceed £3,000 per tax year.
- How do I deposit on Polymarket from the UK?
- UK traders typically fund Polymarket via Coinbase UK, Kraken or Revolut — buying USDC with GBP and transferring to a Polygon-compatible wallet (MetaMask, Coinbase Wallet). Polymarket's onboarding walks you through the bridging process. Typical GBP-to-USDC conversion costs 0.5–1%.
Trade OpenAI IPO by 2026? on Polymarket Alternative UK
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