National Bank Open: Elise Mertens vs Anna Bondar

Platform comparison

Market context

The match is Elise Mertens against Anna Bondar at the National Bank Open, and the market pays out on which player *advances* rather than on who merely starts or leads. In prediction-market terms, a **YES** share means the named outcome happens, while a **NO** share means it does not; with crowd-implied probability at 100% YES, the market is effectively saying Mertens is expected to be the advancing player and is pricing almost no chance of a Bondar advance or a qualifying fallback to 50-50.

Recent form and head-to-head history both point in the same direction. Mertens has a 2-0 head-to-head record against Bondar, including a straight-sets win on hard court in Toronto in 2022, and she also carries the stronger tour-level record overall and on hard courts in the 2026 season snapshots available.[1][2][6] That is the kind of profile prediction markets often compress into a near-certain price: a higher-ranked player, a favourable surface, and a prior win in the same event environment. Even so, a 100% implied probability should be read as market confidence rather than certainty, because tennis markets can still flip if there is a withdrawal, a walkover, or an unplayed match that forces the special 50-50 rule.

The main things to watch are official schedule changes, late injury or illness reports, and whether the match is actually completed within the market’s settlement window. Flashscore listings show the fixture was due around 5–6 August 2026, while the market itself allows for delayed or interrupted play so long as a winner is eventually determined within seven days of the scheduled date.[7][10][17] For traders, the key dependency is simple: if the match is not played at all, ends tied, or drifts beyond that seven-day limit without a winner, it settles 50-50 instead of to either player.

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

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 does Polymarket cost to trade?

Polymarket itself charges 0% — the only cost is the Polygon network fee, typically under $0.01 per transaction. Off-chain venues like Kalshi or Betfair charge 2-7% commission.

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%.