Lexington: Spencer Johnson vs Andres Martin

Platform comparison

Market context

The underlying event is a men’s tennis match between **Spencer Johnson and Andres Martin** in Lexington, scheduled for 7 August 2026 at 2:00pm ET. In prediction-market terms, a **YES** share pays out if the named outcome happens, while a **NO** share pays out if it does not; here, the contract is tied to whether Spencer Johnson advances against Martin, with walkovers, retirements and some non-completions treated separately under the market rules.[12]

The current **100% YES** price is far above the pre-match view in the wider betting and prediction market data, where Johnson was only a modest favourite rather than a lock. Public odds and modelled probabilities around the fixture generally sat in the mid-50s to low-60s for Johnson, with several books listing him around 1.53–1.68 and Martin around 2.03–2.35, which implies a competitive match rather than a near-certainty.[1][4][6][8][10][13][15] Tennis Tonic also tipped Johnson to win, but in three sets, which is another sign that the market was not pricing a straightforward blowout.[1]

For traders, the main catalysts are match status and how the organisers record the result. If the match is played to completion, the contract resolves on the official winner; if it is cancelled, left unresolved beyond the stated delay window, or falls into the market’s exception cases, the payout can shift to **50-50** instead.[12] The key practical checks are the published order of play, any late withdrawal news, and live score updates if the contest starts but does not finish, because those are the events most likely to change the settlement outcome.[5][12][17]

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We track Lexington: Spencer Johnson vs Andres Martin 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

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 Prediction Market 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%.