Philadelphia: Simona Waltert vs Fiona Crawley

Platform comparison

Market context

The Philadelphia women’s singles match between Simona Waltert and Fiona Crawley was listed for 24 August on hard courts, and live score feeds show it was played to completion with Crawley winning 7-5, 6-3.[1][2] For a prediction market, that matters because the likely settlement path shifts away from pre-match win pricing and towards whatever the contract specifies for a completed result, rather than cancellation or tie handling.[1][2]

The relevant historical framing is straightforward: when a match is actually completed, the crowd-implied price tends to collapse quickly towards the recorded winner, whereas zero-liquidity or stale prices can lag until the result is confirmed across multiple feeds. Here, Waltert entered as the higher-ranked player and a seed, but Crawley’s live result removes the usual ranking-based edge from any model that was still relying on pre-start assumptions.[1][2][3]

For a programmatic trader, the main checks are match status, source consistency, and the settlement clock. The useful workflow is to poll the event page, verify the final score from at least two independent live-score sources, and then map the outcome against the market’s resolution rules before the 7 September fallback deadline; if a platform has not updated, an automated watcher should treat the market as stale rather than tradable on the old pre-match line.[1][2][3]

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.

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.

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%.