National Bank Open: Antonia Ruzic vs Madison Keys

Platform comparison

Market context

Polymarket’s contract is trading as a near-certain **Madison Keys** outcome, with the market showing about **82% YES** for Keys and only **18%** for Antonia Ruzic, which is far above the current crowd-implied 1% YES on the other side. The position settles via USDC on Polygon through conditional tokens, so traders are not just betting on who wins on court, but on whether the listed match is completed, postponed, or converted into a 50-50 outcome under the market rules.

That pricing is consistent with the broader pre-match consensus in tennis markets and models, which have also made Keys the clear favourite in this pairing. Recent previews and odds boards have typically put Keys around the low-80s to high-80s on implied win probability, with one current model giving Keys 82.9% and another set of betting prices showing a similar gap; the head-to-head record listed by preview sites is 1-0 to Keys, which reinforces that market shape rather than challenging it. [4][17][7]

What matters now is not a dramatic repricing of baseline strength, but event risk around the scheduled match itself. The live listings show the contest as a National Bank Open second-round match at Grandstand, and Polymarket-style resolution hinges on whether play starts and finishes, or whether a delay/cancellation pushes it into the market’s fallback rule set; if the match is not completed, the settlement mechanics can matter more than the scoreline. In practical terms, traders should watch the official order of play, any last-minute withdrawal notices, and whether the match is moved or delayed beyond the seven-day window, because those are the catalysts that can override a simple favourite-longshot read. [3][13][15]

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page reviews National Bank Open: Antonia Ruzic vs Madison Keys across five venues. The live probability is the Polymarket mid-price, sourced directly from the on-chain Polygon order book; the comparison columns benchmark each venue on fee structure, KYC, settlement currency and payment rails. Every CTA routes to Kalshi UK, which mirrors the Polymarket order book at 0% fees.

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

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.

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%.