Platform comparison
| Platform | YES odds | NO odds | Fee | KYC | Settlement | |
|---|---|---|---|---|---|---|
Polymarket (via Trump Prediction) Pick polygram.ink (preferred broker) |
76% | 24% | 0% (USDC on-chain) | No-KYC up to $1,500 | USDC, auto via UMA oracle | Live odds → |
Polymarket (direct) polymarket.com |
76% | 24% | 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 |
|---|---|
| US Open WTA: Marta Kostyuk vs Ekaterina Alexandrova | 76% |
| US Open WTA: Marta Kostyuk vs Ekaterina Alexandrova Set 2 Winner | 70% |
| US Open WTA: Marta Kostyuk vs Ekaterina Alexandrova Set 1 Winner | 69% |
| US Open WTA: Marta Kostyuk vs Ekaterina Alexandrova Set 1 O/U 8.5 | 68% |
| US Open WTA: Marta Kostyuk vs Ekaterina Alexandrova Set 1 O/U 10.5 | 53% |
| US Open WTA: Marta Kostyuk vs Ekaterina Alexandrova Set Handicap +/-1.5 | 52% |
| Completed Match | 50% |
| US Open WTA: Marta Kostyuk vs Ekaterina Alexandrova Set 2 O/U 8.5 | 50% |
| US Open WTA: Marta Kostyuk vs Ekaterina Alexandrova Set 2 O/U 9.5 | 50% |
| US Open WTA: Marta Kostyuk vs Ekaterina Alexandrova Set 2 O/U 10.5 | 50% |
| US Open WTA: Marta Kostyuk vs Ekaterina Alexandrova Match O/U 21.5 | 48% |
| US Open WTA: Marta Kostyuk vs Ekaterina Alexandrova Game Spread +/-4.5 | 47% |
| US Open WTA: Marta Kostyuk vs Ekaterina Alexandrova Set 1 O/U 9.5 | 46% |
| US Open WTA: Marta Kostyuk vs Ekaterina Alexandrova Match O/U 22.5 | 44% |
| US Open WTA: Marta Kostyuk vs Ekaterina Alexandrova Match O/U 23.5 | 40% |
| US Open WTA: Marta Kostyuk vs Ekaterina Alexandrova Total Sets: O/U 2.5 | 36% |
Market context
Based on real-money crowd forecasting, us open wta: marta kostyuk vs ekaterina alexandrova stands at 76% likelihood according to current market consensus. This market refers to the tennis match between Marta Kostyuk and Ekaterina Alexandrova in the US Open WTA, originally scheduled for September 4, 2026 at 11:00AM ET. This market wi…
Methodology
Political prediction markets differ structurally from sports betting: thinner liquidity, longer settlement windows, higher sensitivity to single news events. This page shows the live Polymarket quote for US Open WTA: Marta Kostyuk vs Ekaterina Alexandrova plus platform attributes for the three reference venues, so you can see at a glance where the deepest market for this question sits.
Resolution & payout
Political markets typically settle on official candidate or agency confirmation. Polymarket uses UMA Optimistic Oracle: a proposer posts the outcome with a bond, the two-hour window opens, then the smart contract pays USDC.
Kalshi settles USD via CFTC clearinghouse, with clearly defined resolution sources (e.g. AP race calls for elections). Betfair settles after the official outcome is registered with the league or agency. Manifold is play-money.
UK Frequently Asked Questions
- How accurate are political prediction markets?
- Historically more accurate than polls. Polymarket's Brier score on US 2024 elections was ~0.11 — better than 538 (~0.14) and every mainstream poll. Markets aggregate information with real skin in the game.
- What resolution source is used for elections?
- Polymarket defines the source per contract — usually Associated Press (AP Race Call), Reuters or the official electoral commission. The source is stated in contract details before the market opens.
- Can prediction markets influence election outcomes?
- Markets reflect expectations rather than create them. Studies show public-facing markets can anchor expectations, but don't influence the underlying outcome. Political markets are information, not advocacy.
- How fast do political markets react to news?
- High-liquidity markets move within seconds to minutes. A Trump tweet on the economy can shift the "Trump 2024" market 2-5 points before mainstream media has written anything.
- Are UK election prediction markets available from the UK?
- Yes. Betfair Exchange and Smarkets offer UKGC-regulated UK election markets (seat counts, party share, constituency results). Polymarket also lists UK election contracts with deeper global liquidity. Betfair winnings are typically tax-free for UK individuals; Polymarket profits are subject to HMRC CGT.
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