PolymarketClosedCheck availabilityNo KYCVerified resolution dataWell calibratedThis market resolved: Down
Resolved: Oct 20, 2026, 10:29 PM
Provider-verified resolution
CoinRithm has provider-backed winner and settlement-time evidence for this market.
Winning Outcome
Down
At 7 days out
—
At 24 hours out
39%
SurpriseData quality warningStale data
Data as of Oct 21, 2026, 12:40 PM UTC · policy pm-quality-4
Probability Timeline
Up0%
Down100%
DownWon
UpLost
Related Markets
Related questions for context, not a comparison of equivalent contracts.
Rules
This market will resolve to "Up" if the official S&P 500 Index open price for S&P 500 (SPX) on October 20 is higher than the official S&P 500 Index closing price for SPX on the most recent prior trading day.
- This market will resolve to "Down" if the official S&P 500 Index open price for S&P 500 (SPX) on October 20 is lower than the official S&P 500 Index closing price for SPX on the most recent prior trading day.
- E.g., ordinarily, a market on Monday would refer to the previous Friday for its most recent closing price, unless that Friday were a market holiday, in which case it would refer to Thursday, or the next most recent trading day.
- If the two prices are exactly equal, this market will resolve 50-50.
- Note that all figures will be rounded to the nearest cent using standard rounding.
- If SPX does not trade at all during the regular session, the market will resolve 50-50.