Probability
How the price has moved
The market opened on 29 July 2026 at 99%, a level consistent with an illiquid contract meeting its first trade rather than a considered forecast. Since then it has ranged from 69% to 100%, and in the last 24 hours it moved by 28.9 percentage points, arriving at the current level. With only $43,505 in total volume and 857 recorded price observations on a single venue, this is best read as a market still in early price discovery a month before the tournament begins, not one that has settled on a stable view.
Analysis
Context
The Women's US Open singles title is decided over a 128-player single-elimination draw at Flushing Meadows, New York, from 23 August to 13 September 2026. To win, a player must survive seven consecutive matches without a loss or withdrawal. Aryna Sabalenka enters as the world No. 1 and is currently the most-backed name in this market, but a Grand Slam draw is long enough that even the top seed is eliminated more years than not.
This particular market only began trading on 29 July 2026, a day before this page was written, and so far only one venue, Polymarket, has listed it. Total volume is $43,505, small next to the political and macro markets this audience typically follows, which matters directly for how much weight to put on any single price move.
The official result, once the tournament concludes, will come from usopen.org, with reporting from other outlets used to corroborate it if needed.
The headline figure to explain here is not the current price, which moves live, but the pattern behind it. When this market was first recorded on 29 July 2026, it showed a probability of 99% — a number that makes little sense for any player, including a world No. 1, entering a seven-round single-elimination draw a month before it starts. That kind of print almost always reflects an empty order book meeting a single small trade, not a considered view of Sabalenka's chances. Since then the price has ranged as widely as 69% to 100%, and it moved by 28.9 percentage points in the last 24 hours alone, settling near 30%. That is a market still searching for equilibrium rather than one expressing a stable consensus.
The scale of that swing is easier to read against the volume: $43,505 across 857 recorded observations on a single venue, Polymarket. That is a large number of price ticks relative to the dollars behind them, which is consistent with a newly listed, thinly traded contract where a handful of participants can move the quoted price sharply without much capital changing hands. For a reader used to deeper markets on Fed decisions or election outcomes, this is a useful contrast: the current level should be read as an early, unsettled estimate, not a mature market's judgment.
On the substance, a figure near 30% is not an unreasonable starting point for the most prominent player in a field that must still be finalised. Being world No. 1 gives Sabalenka the single largest individual probability of any name in the draw, but a 128-player single-elimination bracket on hard courts leaves room for early upsets, fatigue from the North American summer hard-court swing, and the luck of who she is drawn to meet in the second week. None of those variables are yet fixed this far out, which is itself a reason the price is likely to keep moving once the draw is published in mid-August.
What moves the probability
Single-elimination format
A Grand Slam title requires seven consecutive wins with no room for a bad day. This structural fact caps how high any single player's probability can reasonably sit, no matter their ranking.
Thin, newly listed market
With only $43,505 in total volume on one venue, the price can swing on small trades rather than broad consensus. The 28.9-point move in the last 24 hours and the 69%-100% range since listing both point to a market still finding its level.
Draw not yet published
The full 128-player bracket, including who Sabalenka would meet in the later rounds, is not yet known. Publication of the draw, expected in mid-August, is likely to be the next event that moves the price meaningfully.
World No. 1 ranking
Being the top-ranked player keeps Sabalenka the single largest probability in the field even through the current volatility, since ranking is the clearest public signal of current form ahead of the seeding.
Hard-court surface
The US Open is played on hard courts, the surface associated with her ranking-topping results, which supports her standing as favourite relative to players who are stronger on clay or grass.
The case for
- Sabalenka enters as the world No. 1, giving her the highest individual probability of any player in the field according to the market.
- For the market to resolve yes, she must win seven consecutive matches between 23 August and 13 September 2026 without a loss or withdrawal.
- The tournament is played on hard courts, the surface most associated with her current ranking and results.
- A published draw that avoids the toughest seeds in her early rounds would support her chances of reaching the final.
The case against
- Any single loss or withdrawal at any point in the draw resolves the market no, and a 128-player single-elimination bracket offers many chances for an upset.
- The market's own short history — a 99% opening print, a 69%-100% range, and a 28.9-point move in the past day — shows how unsettled even close observers currently are about her chances.
- Other top-ranked players in the field are each capable of ending her run in any given match over the three-week tournament.
- Form and health in the weeks immediately before 23 August 2026, not yet reflected in this market, could shift the outlook before the draw is even made.