National Bank Open: Fabian Marozsan vs Matteo Arnaldi

Platform comparison

Market context

Fabian Marozsan and Matteo Arnaldi are scheduled to meet in Montreal at the National Bank Open, with the market currently pricing Marozsan at 56% despite Arnaldi having the clearer head-to-head edge. The most useful framing for a programmatic trader is that the crowd number is not a pure power rating: it is a blend of draw context, surface, and live scheduling risk, so the first check is whether the match is actually locked into the card and within the settlement window.

The historical read leans towards Arnaldi. The pair have met at least once on the ATP level, with Arnaldi winning their Geneva clay match 6-3, 7-6(3) in 2025, and multiple tennis databases list him as 2-0 or 3-0 in the matchup depending on which events they count. That matters because a bot or conditional-order workflow should not treat 56% as a strong consensus signal; it is only a modest favourite and sits against the only clearly documented completed result, which favours Arnaldi.[1][2][10]

For traders using alerts or automation, the key catalysts are the official order of play, any last-minute withdrawal notice, and whether the match starts before the cut-off. If it is postponed more than seven days beyond the original date without a winner, the market resolves 50-50, so a monitoring script should watch for ATP or tournament updates rather than just scoreboard feeds. The practical dependency is simple: no completed match, no directional resolution, while a started but unfinished match can still settle on the player who advances under the market rules.

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

Settlement runs on-chain. Polymarket's contract logic separates YES and NO shares as conditional tokens; at resolution the winning share lifts to $1.00 and the losing one to $0. The outcome input comes from the UMA Optimistic Oracle, which secures against bad resolution with a bond + dispute window.

Once finalised, the smart contract pays USDC to the holders' wallets within minutes — no withdrawal fees beyond Polygon network gas. Kalshi settles in USD via CFTC clearance, Betfair in account currency net of commission, Manifold in play-money mana with no cash-out.

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.

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%.