Newport: Mananchaya Sawangkaew vs Mary Stoiana

Platform comparison

Market context

The underlying event is the WTA 125K Newport quarterfinal between Thailand’s Mananchaya Sawangkaew and Mary Stoiana, which concluded on 10 July 2026 with Sawangkaew advancing to the semifinals after a 3–6, 6–2, 7–5 victory [6]. The prediction market in question, now showing a 100% YES implied probability for Sawangkaew, reflects the match’s completed outcome rather than a live betting opportunity, creating a stark divergence from any pre-match sportsbook lines that would have treated this as a contest of uncertain result [7].

Historically, prediction markets that lock in at 100% after an event’s resolution—especially in tennis where match results are final and verifiable—tend to settle cleanly without the 50–50 cancellation clause triggering, provided the match was played and a winner determined [1]. Comparable cases from WTA events show that once a player advances, contracts tied to that advancement resolve definitively, with no meaningful lag between result confirmation and market settlement, unlike futures on delayed or weather-affected matches.

Traders should monitor the official WTA schedule for Newport’s semifinal pairings to confirm Sawangkaew’s next opponent, as any withdrawal or injury post-qualification could technically affect downstream markets, though not this settled contract [3]. No further announcements are expected for this specific match, given its completion, but checking Tennis.com or SofaScore for any post-match disciplinary updates or ranking adjustments remains prudent for related trading strategies [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

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.

FAQ

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.

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.

What does Polymarket cost to trade?

Polymarket itself charges 0% — the only cost is the Polygon network fee, typically under $0.01 per transaction. Off-chain venues like Kalshi or Betfair charge 2-7% commission.

How fast are USDC deposits?

Polygon credits deposits after 12 confirmations — usually under 30 seconds. Withdrawals follow the same path and land back in your wallet within minutes.

How reliable are the quoted odds?

The YES/NO percentages are the live mid-prices of the Polymarket order book. On deep markets they move every few seconds; on thinner ones you'll see short plateaus.