Will Aryna Sabalenka win the 2026 Women’s US Open?
Crossbook compares what two exchanges, Polymarket and Kalshi, charge for the same event, and publishes a permanent scored record of its own forecasts under published rules.
Both venues are priced below, side by side.
Informational only. Not trading or investment advice. Prices may be delayed or inaccurate, and a difference between venues can be an artifact — how this is measured.
How each venue defines this
Each exchange's own settlement text, quoted as written. Where they differ, the difference is usually why the prices do.
Settles Sep 13, 26
The 2026 U.S. Open tennis tournament is scheduled for August 23 - September 13, 2026. This market will resolve to the player that wins the 2026 U.S. Open Women’s Singles Tournament. If at any point it becomes impossible for a listed player to win the 2026 U.S. Open Women’s Singles Tournament per the rules of the tournament, the corresponding market will resolve to “No”. If the 2026 U.S. Open Women’s Singles Tournament is cancelled, postponed after October 31, 2026, or there is otherwise no winner declared within that timeframe, this market will resolve to “Other”. The primary resolution so…
Settles Sep 13, 26
If Aryna Sabalenka wins the 2026 US Open Women's Singles professional tennis tournament, then the market resolves to Yes.
Settlement basis
A person confirmed these two markets ask the same question. Their settlement documents have not been compared, so treat the price difference as unverified rather than as a like for like gap.
Confirmed as the same question: Will Aryna Sabalenka win the 2026 Women’s US Open?
Crossbook forecast
No public Crossbook forecast on this market yet. Every call that is made is timestamped and scored on the public record, win or lose.
Context
Polymarket and Kalshi agree on this one. Both price it near 34%, so there is no cross venue disagreement to trade and no basis to speak of.
Volume over the last 24 hours is active, at about $43,494 on the busier venue. It closes in 4 days. Prices this close to resolution move on news rather than on reassessment.
Related markets
Crossbook publishes every forecast it makes, timestamped before the answer is known and scored against the market afterwards. See the public record and the rules it is held to.