National Bank Open: Fabian Marozsan vs Matteo Arnaldi

Platform comparison

Market context

Fabian Marozsan against Matteo Arnaldi is a cleanly priced rematch with the crowd leaning towards **Marozsan at 59% YES**, which leaves the market only mildly bullish rather than decisive. The comparison with prior meetings is awkward for that view: the available head-to-head records show **Arnaldi leading 2-0 or 3-0**, depending on the database, with the most recent meeting in Geneva won **6-3, 7-6(3)** on clay by Arnaldi[3][4][5][7][9]. That makes the prediction-market price look somewhat more favourable to Marozsan than the direct historical matchup would suggest, while still short of a strong contrarian punt.

For traders, the main catalyst is whether the match is confirmed and completed within the settlement window, because an unplayed match, a tie, or a delay beyond seven days would resolve at **50-50** under the contract terms. The original start was set for 5 August at 11:00am ET, so any schedule shifts, walkovers, or late withdrawals matter more here than in a standard win-only market. On performance context, both players have shown enough recent competitiveness on hard courts and in best-of-three formats to keep price volatility alive, but the last clear match evidence still favours Arnaldi’s head-to-head edge and service stability in their previous encounter[7][9][11].

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We track National Bank Open: Fabian Marozsan vs Matteo Arnaldi 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

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

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 UK. Kalshi charges up to 7% per trade; Betfair Exchange takes 2-5% commission on net winnings.

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.

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 are the best prediction markets for UK traders in 2026?

For UKGC-regulated markets: Betfair Exchange (sports, politics) and Smarkets (sports, politics, lower commission than Betfair). For broader global event prediction: Polymarket (deepest liquidity, 0% fee, USDC settlement). For US-regulated option: Kalshi (USD, limited UK payment options). Most serious UK traders use a combination of Betfair for regulated sports and Polymarket for broader markets.