National Bank Open (Doubles): Jiang/Wu vs Mertens/Shnaider

Platform comparison

Market context

Polymarket is pricing the Jiang/Wu v Mertens/Shnaider doubles contract at **0% YES** today, which means the market is effectively saying Jiang/Wu have no remaining path to be the named advancing team under the contract rules. On Polymarket, the position is traded in **USDC** on **Polygon**, with the outcome embedded in conditional tokens rather than a simple bookmaker-style bet, so the relevant question is whether the match has already produced the settlement outcome, or whether it is still unresolved within the rule set. [1][5]

For context, outside markets have treated Mertens/Shnaider as the stronger side throughout the matchup, with Tennis.com listing them as the projected winner and other odds screens showing them around the 1.26–1.35 range versus roughly 3.0–3.5 for Jiang/Wu. That kind of pricing is consistent with a near-certain favourite, and it helps explain why a Polymarket contract can sit at the floor even before the final on-chain settlement state is obvious. The important distinction for a trader is that Polymarket resolves on the match outcome and its timing rules, not on pre-match rankings or in-play dominance. [2][6][7][11]

The main catalysts are straightforward: an official match result, a confirmed retirement or walkover, or any scheduling change that pushes the contest outside the market’s seven-day window. Polymarket’s own market text says that if the match begins but is not completed, or if it is cancelled before play, the market can resolve 50-50; if Jiang/Wu were to advance, the contract pays that side, otherwise Mertens/Shnaider does. Tournament listings and live-score pages are the places to watch for whether the pairing actually took court and whether the scoreline has been completed, while late updates from the National Bank Open schedule are the key dependency for any delayed-resolution scenario. [1][2][17]

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

At resolution the UMA oracle takes over: a proposer posts the outcome with a bond, any token holder can dispute within two hours. Without dispute the result is accepted and the smart contract distributes USDC instantly.

On Kalshi (CFTC-regulated) resolution runs through their in-house clearing engine in USD. Betfair Exchange settles after match end in the account's local currency. Manifold pays no cash — only its in-platform "mana" currency.

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 Kalshi 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.

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%.