Cincinnati Open: Sloane Stephens vs Sinja Kraus

Platform comparison

Market context

Sloane Stephens and Sinja Kraus were due to meet in the Cincinnati Open first round on 14 August 2026, with live scoring and broadcast listings appearing on match-day schedules and Tennis.com showing the contest as underway. The market’s 88% implied probability reflects a strong expectation that the match will produce a clear winner rather than drift into a no-contest outcome.

The main historical frame is straightforward: in women’s WTA 1000 events, scheduled first-round matches usually resolve on court, and markets that trade above 80% are generally signalling that the listed favourite is expected to advance unless there is a withdrawal, retirement or rain interruption. That leaves limited room for a true 50-50 settlement unless the match is not completed within the market’s defined window.

For traders, the key catalyst is whether the match is officially completed before the 21 August settlement deadline, rather than any broader tournament narrative. The live scoreboards and match listings pointed to a normal start time on 14 August, while the main dependency is the official result: a straight completion favours a clean winner, but a cancellation, no-show, or unresolved suspension would push settlement towards 50-50 under the market rules.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page tracks Cincinnati Open: Sloane Stephens vs Sinja Kraus across four political prediction venues. Live odds come from the Polymarket order book (the deepest political prediction-market book). Kalshi is the CFTC-regulated US alternative, Betfair the established UK sports-exchange with politics markets, Manifold the open play-money variant. For users geo-blocked from Polymarket directly, brokers like Trump Prediction provide a 0%-fee route into the same order book.

Resolution & payout

Political markets typically settle on official candidate or agency confirmation. Polymarket uses UMA Optimistic Oracle: a proposer posts the outcome with a bond, the two-hour window opens, then the smart contract pays USDC.

Kalshi settles USD via CFTC clearinghouse, with clearly defined resolution sources (e.g. AP race calls for elections). Betfair settles after the official outcome is registered with the league or agency. Manifold is play-money.

UK Frequently Asked Questions

What resolution source is used for elections?

Polymarket defines the source per contract — usually Associated Press (AP Race Call), Reuters or the official electoral commission. The source is stated in contract details before the market opens.

Can prediction markets influence election outcomes?

Markets reflect expectations rather than create them. Studies show public-facing markets can anchor expectations, but don't influence the underlying outcome. Political markets are information, not advocacy.

Which platform has the deepest political liquidity?

Polymarket — by far. US 2024 presidential volume was ~$3.5B vs Kalshi (~$200M) and Betfair (~$120M). Where Polymarket is geo-blocked, brokers like Trump Prediction route into the same order book at 0% fees.

How fast do political markets react to news?

High-liquidity markets move within seconds to minutes. A Trump tweet on the economy can shift the "Trump 2024" market 2-5 points before mainstream media has written anything.

Are UK election prediction markets available from the UK?

Yes. Betfair Exchange and Smarkets offer UKGC-regulated UK election markets (seat counts, party share, constituency results). Polymarket also lists UK election contracts with deeper global liquidity. Betfair winnings are typically tax-free for UK individuals; Polymarket profits are subject to HMRC CGT.