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Will Alexander Bublik win the 2026 Men'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.

Settlement equivalence unverified. No eligible price gap is available.

SettledContract settles 13 Sept 2026Last checked 4 Sept 2026, 19:50 UTC
PM

Bid/ask midpoint · retrieved 2026-09-04T19:50:26.666Z. Venue quote-update time is unavailable. Readings can be asynchronous.

0.7%bid 0.5% / ask 0.9%24h volume $819 · liquidity $49Kas of 4 Sept, 19:50 UTC · not refreshed recentlyView on Polymarket
KS

Bid/ask midpoint · retrieved 2026-09-13T21:50:26.487Z. Venue quote-update time is unavailable. Readings can be asynchronous.

no two-sided marketnobody is quoting both sides, so there is no price to show24h volume $487K · liquidity –as of 13 Sept, 21:50 UTC · not refreshed recentlyView this market's series on Kalshi

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 Men’s Singles Tournament. If at any point it becomes impossible for a listed player to win the 2026 U.S. Open Men’s Singles Tournament per the rules of the tournament, the corresponding market will resolve to “No”. If the 2026 U.S. Open Men’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 source w…

Settles Sep 14, 26

If Alexander Zverev wins the 2026 US Open Men's Singles professional tennis tournament, then the market resolves to Yes.

Settlement basis

Settlement equivalence unverified

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 Alexander Bublik win the 2026 Men's US Open?

Crossbook forecast

13.0%against a market price of 0.5% at the timeNO

Logged 29 Aug 2026, 03:34 UTC · Brier 0.0169

  • The tournament is already in progress (started Aug 23, today is Aug 29), so pre-tournament base rates are only a starting point; mid-event survival sharply updates odds for anyone still alive.
  • The 22-point cross-venue spread (0.5% polymarket vs 23% kalshi) strongly suggests the polymarket book is a stale pre-tournament resting book while kalshi's $40k of 24h volume reflects live information — most plausibly that Bublik has advanced deep into the draw (e.g., quarterfinal or better) and possibly that favorites have been eliminated from his half.
  • I discount kalshi's 23% somewhat because Bublik has never beaten the true elite tier in best-of-five at Slams, and winning two or three more matches against likely Sinner/Alcaraz-caliber opposition is harder than a thin, momentum-driven book may imply; landing near 12–14% respects both the live signal and his underlying level.
  • If instead the kalshi price is itself stale or a mislabeled contract, 0.5–2% is the right range — this ambiguity is why confidence is low and I weight heavily toward the middle rather than fully trusting either venue.

What would change it: Confirmed draw information showing Bublik is already eliminated (estimate drops to ~0) or that he is in the semifinal/final with top seeds out (estimate rises toward 25–35%).

Settlement source

+12.4 probability points from the market at generation · low confidence · Polymarket

Base rate: A non-elite player outside the Sinner/Alcaraz/Djokovic tier enters a hard-court Slam with roughly a 1–3% chance of winning the title pre-tournament.

Chosen by hand.

Settlement

Every answer this call has been given, oldest first. Nothing is edited: a correction is a new entry beside the one it replaces.

  1. VOIDsettled 15 Sept 2026, 01:38 UTC · recorded 15 Sept 2026, 01:38 UTC · entered by handsettlement

  2. NOsettled 4 Sept 2026, 23:20 UTC · recorded 5 Oct 2026, 01:23 UTC · read from the venuesettlement

    Corrected against Polymarket's settlement. Recorded VOID on 15 Sept 2026; Polymarket settled NO on 4 Sept 2026. VOID means the venue refunded or cancelled the market, which it did not.

Context

Settlement equivalence unverified. The venue readings below are not ranked as a comparable price gap.

Volume over the last 24 hours is heavy, at about $487,135 on the busier venue. At least one side of this market has no real two sided book, which means the quoted price is closer to a placeholder than to a traded level.

This market has settled. The page is kept as a record of what both venues said while the question was open, and of what Crossbook called.

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.

This call is line t-0071 of the public append-only ledger, committed when it was published. It appears on the record alongside every other call, resolved and open.