Libema Open: Caty McNally vs Solana Sierra

Platform comparison

Active sub-markets

Market context

The Libema Open in 's-Hertogenbosch is a grass-court tournament on the WTA calendar, scheduled for June 2026. This market concerns a first-round match between American Caty McNally and Colombian Solana Sierra, originally set for 11 June at 4:00 AM ET. A YES share represents a bet that McNally advances; a NO share bets on Sierra's progression. The current crowd-implied probability of 57% for McNally reflects modest confidence in her favour, suggesting meaningful uncertainty about the outcome.

McNally, a former top-50 player with mixed results on grass, has struggled with consistency in recent seasons but retains baseline solidity and serve strength. Sierra, ranked lower and with limited WTA grass-court exposure, represents a less predictable opponent. Historical patterns in early-round grass-court matches show that seeding and recent form matter substantially, though upsets occur at elevated rates on this surface compared to clay or hard courts. The relatively narrow 57% probability suggests traders view this as genuinely competitive rather than a clear favourite situation.

Key variables to monitor include official draw confirmation and any late withdrawals or injury announcements before 11 June. Weather conditions at 's-Hertogenbosch—particularly rain, which could delay play—matter given the settlement window closes 18 June; extended delays beyond seven days trigger a 50-50 resolution. Recent WTA injury reports and either player's performance at preceding events will provide concrete form signals. The early morning scheduling may also influence match dynamics and player preparation patterns.

Methodology

We track Libema Open: Caty McNally vs Solana Sierra on the five venues with material liquidity for prediction markets. Live odds come from the Polymarket Polygon order book — the only source that ships real-time data under an open licence. For Kalshi, Betfair and Manifold we list platform attributes (fee, KYC, settlement, payment) instead of fabricated odds, because their APIs use non-comparable contract definitions.

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

Is this market available outside the US?

Prediction Market UK is available in most jurisdictions where Polymarket isn't directly accessible. Polymarket itself is geo-blocked in the US/UK/EU. Always check local regulations.

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 it cost to trade on Prediction Market UK?

Zero. Prediction Market UK routes every order to the live Polymarket order book; the only cost is the Polygon network fee, typically under $0.01 per transaction.

Do I need to KYC for this market?

Not under $1,500 of lifetime trading volume. Above that threshold, Prediction Market UK triggers a quick verification flow that finishes in minutes.