National Bank Open: Jacob Fearnley vs Jakub Mensik

Platform comparison

Market context

Jacob Fearnley and Jakub Mensik are set to meet in Montreal, and the market has already priced Mensik as the more likely winner, with the crowd at 18% for Fearnley. The most relevant change in the last day is simply that the match has moved from preview stage into live scheduling territory, so the main near-term question is whether the contest is played on time and produces a straight winner before the market’s settlement cut-off.

The historical frame points more towards Mensik. The pair have no recorded head-to-head matchups, so traders are leaning on broader form rather than direct evidence[1][2][14]. Mensik’s last-52-weeks record is materially stronger, at 34-20 with a 63.0% win rate, while Fearnley is close to break-even at 29-28[1]. On hard courts, the surface used here, Fearnley’s career ATP record is weaker than Mensik’s, and one preview site notes that Mensik has been the more efficient hard-court winner despite the gap in ranking[1][16]. That helps explain why the underdog side is still attached to a sub-20% price.

The catalysts to watch are straightforward: official order-of-play updates, any late change to start time, and whether the match is completed within the settlement window. If play is pushed back more than seven days from the scheduled date without a winner, the market would settle 50-50, so a postponement rather than a result is the key non-tennis risk here. Live match listings already show the fixture on 5 August 2026, which suggests the event is being tracked as an active first-time meeting rather than a speculative pairing[4][10][13][14].

Sources: 1 · 2 · 3 · 4 · 5

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.

UK Frequently Asked Questions

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 Prediction Today. 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.

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%.