National Bank Open: Lois Boisson vs Antonia Ruzic

Platform comparison

Market context

Loïs Boisson and Antonia Ruzic were due to meet in the first round of the National Bank Open on outdoor hard courts in Toronto, with published schedules placing the match on 2 August and several live-score services listing Court 4 around 18:00 UTC. The market’s 73% crowd-implied probability is directionally consistent with Ruzic being the higher-ranked player in the pre-match listings, where Boisson was shown around WTA No. 292 and Ruzic around No. 55, while head-to-head records were 0-0.[1][2][3][6]

For comparison, the same matchup was priced more softly on some sportsbook-style pages, but the more important distinction is how the venues express the edge: Polymarket and Kalshi-style contracts are read as direct probabilities, while Betfair and Smarkets show decimal odds and then apply commission, so a 73% market-implied price is not the same as a 1.37 decimal quote net of fees. Availability also differs: exchange-style and prediction-market access depends on jurisdiction and KYC, whereas broader sportsbook access is often more restricted to regulated betting states or countries, so the same tennis view can appear at different effective prices for different users.[18][19]

The main catalysts are simple but operational: any official order-of-play change, weather delay, or withdrawal before first serve can move this market sharply, because if the match is not played or is pushed beyond the seven-day settlement window it resolves to 50-50 under the contract rules. Traders also need to watch the tournament draw flow, since a retirement after the match begins can still determine who advances, and schedule updates from the event or live scoring feeds are the fastest indicators of whether the current probability is still anchored to a played match.[4][5][17]

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page compares National Bank Open: Lois Boisson vs Antonia Ruzic specifically across Polymarket, Kalshi, Betfair Exchange and Smarkets. The live probability is the Polymarket mid; the comparison columns summarise each venue's fee structure, KYC, settlement currency and payment rails. Every CTA routes to Kalshi Alternative, which mirrors the Polymarket order book at 0% fees.

Resolution & payout

Polymarket settles via UMA Optimistic Oracle on Polygon. A proposer posts the outcome with a bond, the two-hour window runs, then the smart contract pays USDC.

Kalshi settles USD through the CFTC-regulated clearinghouse — the cleanest variant, with heavier KYC. Betfair Exchange settles in account currency (GBP/EUR), net of 2-5% commission. Smarkets follows the same model as Betfair with a lower default 2% commission.

FAQ

What does Polymarket cost vs Kalshi?

Polymarket: 0% fees, only Polygon network costs (~$0.01/trade). Kalshi: up to 7% per trade plus spread. For high-frequency traders, Polymarket is dramatically cheaper.

Which platform has the deepest liquidity?

Polymarket — by a wide margin. Top markets reach $50-500M volume, Kalshi ~$200M cumulative, Betfair similar. Deeper liquidity means your trade moves the quote less.

Is Betfair a Polymarket alternative?

Only partially. Betfair Exchange is UK-focused with a sports-betting emphasis; they have politics markets but with thinner liquidity than Polymarket. Settlement in GBP/EUR, 2-5% commission on winnings.

What about Smarkets as an alternative?

Smarkets is a UK betting exchange with a lower default commission (2%) than Betfair. Liquidity on political markets is below Polymarket, comparable to Kalshi. Geo-blocked in many jurisdictions.

Which platform supports Klarna/SOFORT?

Directly: none. Polymarket accepts only USDC on Polygon. Kalshi Alternative offers a fiat on-ramp via Klarna or SOFORT (DE/AT/CH) and converts internally to USDC for the Polymarket order book. T+1 processing.