National Bank Open: Joao Fonseca vs Ben Shelton

Platform comparison

Market context

Polymarket prices **Joao Fonseca at 47%** to advance against Ben Shelton, with the contract settling in USDC on Polygon through conditional tokens rather than a simple sportsbook-style bet. That means the market is effectively trading the probability of Fonseca winning the match, while the contract’s rules still matter: if it is not played, ends in a tie, or is delayed beyond seven days without a winner, it resolves 50-50.

The current price sits close to outside-market sentiment. Polymarket’s own ATP page shows Fonseca around 47% and Shelton around 54% across the match and related in-play contracts, while Tennis Tonic and Sporting Life both lean Shelton as the marginal favourite, with one preview calling Shelton to win in three sets and another listing him at 4/5.[3][1][4] Other tennis-preview sites are less decisive, with Tennis.com giving Shelton only a narrow 52% projected win chance and other match pages showing the pair much closer than a clear mismatch.[5][8][9] For Polymarket users, that kind of split usually supports a mid-range price rather than a strong one-sided move.

The main catalysts are scheduling and tournament progression. The National Bank Open match page lists Fonseca vs Shelton for the round-of-16 window, so any delay, walkover, or injury news from earlier rounds can quickly alter the contract’s path to resolution.[14][5] Market participants should also watch for last-minute lineup updates, court assignment, and any ATP or broadcaster schedule changes, because tennis contracts can shift sharply if a start time slips or a player withdraws before first serve; Polymarket’s match page already shows active volume and a separate 50-50 completed-match contract, underlining how the resolution mechanics can diverge from a normal win market.[6][3]

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page reviews National Bank Open: Joao Fonseca vs Ben Shelton 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 Polymarket Alternative UK, which mirrors the Polymarket order book at 0% fees.

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.

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%.