National Bank Open: Diane Parry vs Kayla Day

Platform comparison

Market context

Diane Parry and Kayla Day are set to meet in the National Bank Open first round, and prediction-market shares here are a simple wrapper around that result: a **YES** share pays out if Parry advances, while a **NO** share pays out if Day advances. The market also has a fallback rule: if the match is not played, ends level, or is delayed by more than seven days without a winner, it resolves 50-50 rather than to either player.[3][15]

For context, the market price needs to be read against the match-up itself rather than the headline ranking gap. Parry is listed around WTA No. 60 and Day around No. 127, and Tennis.com’s pre-match projection has Parry at 48% and Day at 52%, which is close enough to show that the contest is not being treated as a runaway either way.[3] There is also no recorded head-to-head at tour level in the sources provided, so traders cannot lean on a direct recent match-up history to break the tie.[2][15]

The main catalysts are straightforward: the official start, any late change to the order of play, and whether either player withdraws or retires once the match begins. Live score pages already indicate the match is in progress, so the key question for settlement is whether one player completes the job on court or whether an interruption, retirement, or abandonment triggers the market’s special rules.[1][10][13] In practical terms, that means the probability can move quickly on scoreboard events, but the settlement outcome still depends on the event being completed in line with the market rules.[3]

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We track National Bank Open: Diane Parry vs Kayla Day across the five venues with material prediction-market liquidity. The probability shown is the live Polymarket mid; the comparison rows summarise how each venue treats the underlying contract — fees, KYC thresholds, settlement currency, deposit options. The highlighted row marks the cheapest route into Polymarket's order book.

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

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

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.

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.