Cincinnati Open: Sloane Stephens vs Anastasia Potapova

Platform comparison

Market context

Sloane Stephens and Anastasia Potapova were scheduled to meet in Cincinnati on 16 August, and the market now needs to be read against whether the match was actually played and completed within the settlement window. Live scoreboards and match pages show the contest as completed, with Stephens beating Potapova in straight sets, which would point the market to Stephens rather than a default 50-50 outcome if that result stands.

The 100% crowd-implied probability is only sensible if the crowd is treating the event as effectively over and fully resolved. In tennis markets, that kind of unanimity usually reflects late confirmation that a match has begun and finished, not a balanced view of who should win. Comparable cases on WTA events often swing sharply once official scoreboards update, because unfinished or delayed matches can still leave settlement exposed to cancellation, retirement, or a later resumption inside the seven-day rule.

The main catalyst to watch is whether the official tournament scoreboard remains final and whether any correction appears on the event page or draw sheet. If the completed result is retained, the market should settle to Stephens; if an administrative change shows the match was not played to completion, or was voided within the rules, the fallback becomes 50-50. The key dependency is official confirmation from the tournament and tour score feeds, not third-party previews or pre-match listings.

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Methodology

This page reviews Cincinnati Open: Sloane Stephens vs Anastasia Potapova across five venues. The live probability is the Polymarket mid-price, sourced directly from the on-chain Polygon order book; the comparison columns benchmark each venue on fee structure, KYC, settlement currency and payment rails. Every CTA routes to Prediction Today, which mirrors the Polymarket order book at 0% fees.

Resolution & payout

Polymarket-based markets settle through the UMA Optimistic Oracle on Polygon. A proposer submits the outcome, a two-hour challenge window opens, and unchallenged proposals finalise the resolution. Payouts settle automatically in USDC the moment the result is final — no bookmaker, no delay.

Kalshi-based markets settle in USD via the CFTC-regulated clearinghouse. Betfair Exchange settles in GBP/EUR net of commission. Manifold is play-money and does not pay out real funds.

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 Today. Kalshi charges up to 7% per trade; Betfair Exchange takes 2-5% commission on net winnings.

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.

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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.

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