Roehampton: Oliver Tarvet vs Charles Broom

Platform comparison

Market context

Oliver Tarvet and Charles Broom are scheduled to meet in a professional tennis match at Roehampton on 20 August 2026, with the contest originally timetabled for 6:00 AM ET. In prediction-market terms, a YES share represents a bet on Tarvet's advancement past Broom; a NO share backs Broom. The current crowd-implied probability of 86% YES reflects strong market conviction that Tarvet will progress, though the settlement window extends to 27 August, allowing a week's grace for rescheduling before the market resolves to a 50-50 tie outcome if no winner emerges.

Roehampton tournaments historically feature competitive draws across multiple rounds, and early-round matches between lower-ranked or unseeded players often exhibit tighter margins than crowd probabilities suggest. The 86% weighting towards Tarvet implies either a significant ranking or recent-form advantage, or that Broom carries injury or availability concerns. Comparable ATP Challenger or ITF-level matches at similar venues have occasionally produced upsets when the lower-seeded player enters with momentum or favourable court conditions, though such reversals typically occur at probabilities below 75%.

Traders should monitor official ATP or tournament communications for any withdrawal announcements, schedule changes, or surface adjustments in the days before 20 August. Weather disruptions at Roehampton are not uncommon in late summer, and the early morning slot increases the risk of overnight delays. Injury bulletins or late-draw alterations released within 48 hours of the match could shift the probability materially, particularly if Tarvet's recent form or physical condition becomes public knowledge.

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

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.

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%.