National Bank Open: Sara Bejlek vs Iga Swiatek

Platform comparison

Market context

Sara Bejlek’s meeting with Iga Swiatek at the National Bank Open is priced like a heavy underdog for the Czech, with the market implying only a 6% chance she comes through. That sits comfortably with the established matchup: Swiatek beat Bejlek 6-2, 6-3 at Roland Garros in May 2026, and the broader head-to-head still reads 1-0 to Swiatek, with the only completed contest decided in straight sets.[9][11][16] On recent form, the same source set also shows Swiatek’s 2026 win rate running at about 70.8% and Bejlek’s at 64.7%, but the ranking gap and prior Grand Slam result still point the market towards the world No. 3 as the default winner.[1][2]

For traders, the main catalyst is simply whether the scheduled match is actually played on time and whether Swiatek is confirmed in the draw with no late withdrawal or retirement issue. The market’s rules mean a cancellation, tie, or delay beyond seven days forces a 50-50 settlement, so early-round scheduling and any official tournament order-of-play changes matter more than usual. The immediate reference point is the last completed head-to-head, which showed Swiatek’s edge in first-serve points won, return pressure, and break conversion, suggesting the current price is leaning on that prior result rather than on a broader upset narrative.[9][12][13]

Sources: 1 · 2 · 3 · 4 · 5

Methodology

Political prediction markets differ structurally from sports betting: thinner liquidity, longer settlement windows, higher sensitivity to single news events. This page shows the live Polymarket quote for National Bank Open: Sara Bejlek vs Iga Swiatek plus platform attributes for the three reference venues, so you can see at a glance where the deepest market for this question sits.

Resolution & payout

Political markets typically settle on official candidate or agency confirmation. Polymarket uses UMA Optimistic Oracle: a proposer posts the outcome with a bond, the two-hour window opens, then the smart contract pays USDC.

Kalshi settles USD via CFTC clearinghouse, with clearly defined resolution sources (e.g. AP race calls for elections). Betfair settles after the official outcome is registered with the league or agency. Manifold is play-money.

FAQ

How accurate are political prediction markets?

Historically more accurate than polls. Polymarket's Brier score on US 2024 elections was ~0.11 — better than 538 (~0.14) and every mainstream poll. Markets aggregate information with real skin in the game.

Can prediction markets influence election outcomes?

Markets reflect expectations rather than create them. Studies show public-facing markets can anchor expectations, but don't influence the underlying outcome. Political markets are information, not advocacy.

Are political prediction markets legal in my country?

It varies. They sit in legal gray areas in most jurisdictions. Polymarket is geo-blocked from US/UK/EU; some broker frontends have a different geo footprint. Trade only with capital you can afford to lose, and only if you understand the legal status in your jurisdiction.

Why do Polymarket and Kalshi differ on elections?

Kalshi must follow CFTC compliance — strict definitions, clear resolution sources, US citizens only with KYC. Polymarket operates globally without CFTC oversight — deeper liquidity, but also higher regulatory risk.

Which political events have the biggest volume?

US Presidential election, party nominations (DNC/RNC), Senate majorities, individual state outcomes (Pennsylvania, Michigan, Wisconsin), and major European elections. Peak markets reach $50-500M per event.