Livesport Prague Open, Qualification: Sofia Costoulas vs Ayla Aksu

Platform comparison

Market context

Sofia Costoulas has already defeated Ayla Aksu 2–0 in their WTA match at the Livesport Prague Open, with the contest taking place on 19 July 2026 [1]. The prediction market in question, which currently shows a 100% implied probability for Costoulas advancing, reflects this completed outcome rather than an open contest. In live prediction markets, contracts tied to finished events often lock at extreme probabilities once the result is confirmed, creating a divergence from pre-match sportsbook lines that would have offered balanced odds before the match began.

Historically, similar cases in tennis prediction markets—such as those for completed Grand Slam qualifiers—show that once a match result is officially recorded, implied probabilities converge to 100% for the winner, regardless of earlier market fluctuations. This pattern mirrors outcomes seen in Kalshi’s sports contracts, where post-result liquidity collapses and prices stabilise at certainty levels, contrasting with Polymarket’s tendency to retain higher trading volume in such settled scenarios due to its global user base.

Traders should monitor official WTA match reports and tournament archives to confirm the result’s finality, as any discrepancy could trigger a 50–50 resolution under the market’s cancellation clause [2]. No further announcements or schedule changes are expected, given the match has concluded. The key dependency is the absence of a post-match appeal or disqualification, which remains unlikely based on current WTA disciplinary records.

Sources: 1 · 2

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.

FAQ

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.

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.

Do I need to KYC for this market?

On Polymarket directly, no — it's wallet-based. Intermediary brokers like PolyGram trigger KYC only above $1,500 of lifetime trading volume; under that you trade pseudonymously with a single wallet address.

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.