Platform comparison
| Platform | YES odds | NO odds | Fee | KYC | Settlement | |
|---|---|---|---|---|---|---|
Polymarket (via Who Will Win) Pick polygram.ink (preferred broker) |
6% | 94% | 0% (USDC on-chain) | No-KYC up to $1,500 | USDC, auto via UMA oracle | Live odds → |
Polymarket (direct) polymarket.com |
6% | 94% | 0% | Geo-blocked in US/UK/EU | USDC, on-chain | Live odds → |
Kalshi kalshi.com |
— | — | Up to 7% per trade | US-only, KYC required | USD | Live odds → |
Betfair Exchange betfair.com |
— | — | 2-5% commission | Full KYC from first trade | GBP / EUR | Live odds → |
Manifold Markets manifold.markets |
— | — | Play-money (mana) | None — play-money | Mana (no cash-out) | Live odds → |
Outcome probabilities
Current market-implied probability for each outcome, from the live order book.
| Outcome | Probability |
|---|---|
| December 31 | 6% |
| September 30 | 2% |
| April 30 | 0% |
| June 30 | 0% |
| May 31 | 0% |
| March 31 | 0% |
Market context
At **0% YES**, the market is treating an official US confirmation of extraterrestrial life as essentially absent from the policy record, and that is consistent with the government’s repeated line that it has *no evidence* aliens exist or that UAPs are extraterrestrial in origin.[1][7][15][16] The favourite here is clearly **No**. A small contrarian case exists only because the subject keeps resurfacing in hearings, disclosures and media cycles, but those episodes have so far produced ambiguity, not a definitive statement from the President, Cabinet, Joint Chiefs or a federal agency.[1][6][18]
History matters here: the strongest comparable cases have all fallen short of confirmation. NASA’s 2022 review found no evidence supporting extraterrestrial visitation, the Pentagon’s 2024 historical assessment said no US review had confirmed UAP as alien technology, and the 2026 document releases have been framed as unresolved records rather than proof.[2][7][13][16][18] That leaves the current price vulnerable to a classic prediction-market handicapper’s note: the consensus is heavily on **No**, but the only value on **Yes** would come from a surprise shift in official tone, not from another batch of files or witness testimony.
The catalysts to watch are straightforward: any White House comment, a defence or intelligence briefing, a NASA or AARO update, or a formal agency document that goes beyond “unexplained” and says extraterrestrial life or technology *does* exist.[1][4][8][16] On the schedule side, the ongoing UFO/UAP disclosure process launched in 2026 remains relevant because it can move headlines without moving the settlement standard, which requires a definitive official statement.[2][14][18] Traders should also track congressional hearings and closely read agency language, because recent coverage has repeatedly shown that dramatic testimony and “historic” document drops still do not amount to confirmation.[1][5][6]
Methodology
Methodologically we separate two layers: the live probability (Polymarket mid-price) and the platform attributes (fee, KYC, settlement currency, payment rails). That keeps the comparison honest — a single canonical probability across the row, with the venue-by-venue trade-offs spelt out in the columns next to it.
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.
FAQ
- 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 Who Will Win. Kalshi charges up to 7% per trade; Betfair Exchange takes 2-5% commission on net winnings.
- Is this market available outside the US?
- Polymarket itself is geo-blocked in the US/UK/EU. Always check the legal status of prediction markets in your jurisdiction before trading.
- 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.
- What does Polymarket cost to trade?
- Polymarket itself charges 0% — the only cost is the Polygon network fee, typically under $0.01 per transaction. Off-chain venues like Kalshi or Betfair charge 2-7% commission.
- Do I need to KYC for this market?
- On Polymarket directly, no — it's wallet-based. Intermediary brokers like Who Will Win trigger KYC only above $1,500 of lifetime trading volume; under that you trade pseudonymously with a single wallet address.
Trade Will the US confirm that aliens exist by 2027? on Who Will Win
Live order book, 0% fees, USDC settlement in seconds.
Open live market →