National Bank Open: Aryna Sabalenka vs Ekaterina Alexandrova

Platform comparison

Market context

Polymarket is pricing Aryna Sabalenka at **74% YES** on a contract that resolves on the winner of her National Bank Open match with Ekaterina Alexandrova, with settlement routed through Polygon and USDC-backed conditional tokens. The exchange view is slightly more cautious than several tennis models and preview pages, which have Sabalenka around the low-80s and higher in some cases, so the current price sits in the zone where the favourite is clear but not fully banked.[1][3][10]

That read is consistent with the broader hard-court context. Sabalenka arrived as world No. 1 and has been described by Polymarket’s own market page as holding an elite 23-1 hard-court record in 2026, while Alexandrova entered as the lower seed and the more obvious upset path. The pair have met repeatedly, and preview material frames this as a matchup that often rewards the top seed, which is one reason the market has stayed well above parity rather than drifting towards a coin flip.[10][9]

For traders, the main catalyst is simple: whether the match actually goes ahead and is completed inside the market’s timing rules. Tennis.com and official scheduling pages list the fixture at Centre Court on 8 August, while Sportsnet’s match schedule had it on the night slate “not before 7 p.m.” ET, so any reshuffle, rain delay, or order-of-play change is the immediate risk to monitor.[1][4][5] If the contest is not played, or is delayed beyond seven days without a winner, the contract goes 50-50; if play starts but is later abandoned, the eventual settlement will depend on whether a winner is already determined under the market rules.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We track National Bank Open: Aryna Sabalenka vs Ekaterina Alexandrova 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.

UK Frequently Asked Questions

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.

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%.