National Bank Open: Marta Kostyuk vs Iga Swiatek

Platform comparison

Market context

Marta Kostyuk and Iga Swiatek meet in the National Bank Open round of 16 on outdoor hard courts in Toronto, with the market implying a meaningful edge for Swiatek but not a dominant one. The crowd price of 72% on Swiatek sits close to Tennis Temple’s 69.1% match projection and above Tennis.com’s 57% projected winner line, suggesting the prediction market is somewhat more confident than at least one analyst model, though not wildly out of step with the broader tennis market.[1][2][13]

The historical frame is mixed rather than one-sided. Swiatek leads the head-to-head 3-1, including two wins on hard courts, yet Kostyuk won their most recent meeting at Roland Garros in straight sets, 7-5, 6-1, which is a reminder that recent form and surface-specific dynamics can outweigh overall rivalry history.[1] That tension helps explain why this contract is trading below a near-lock despite Swiatek’s stronger baseline status; comparable markets on the same matchup across tennis preview sites have also leaned towards Swiatek, but with different degrees of confidence.[2][9]

For traders, the main catalysts are straightforward: confirmed order of play, whether the match stays on the scheduled Centre Court slot, and any late fitness or withdrawal news. The tournament’s own results pages show the fixture as a round-of-16 match on 8 August, and National Bank Open reports on recent days have already tracked both players through the draw, indicating this is an active live-bracket dependency rather than a speculative booking.[3][5][11] Because the contract resolves 50-50 if the match is not played or is delayed beyond seven days without a winner, schedule disruption matters as much as form.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We track National Bank Open: Marta Kostyuk vs Iga Swiatek across the five venues with material prediction-market liquidity. The probability shown is the live Polymarket mid; the comparison rows summarise how each venue treats the underlying contract — fees, KYC thresholds, settlement currency, deposit options. The highlighted row marks the cheapest route into Polymarket's order book.

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 Best Prediction Markets. 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.

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.

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.