S&P 500 (SPX) Opens Up or Down on October 20?

As of Tue, 20 Oct 2026 13:32:55 UTC, Polymarket traders price Yes (0.1%). The market has $10K in volume and closes on Tue, 20 Oct 2026.

Updated:

Current odds

OutcomeChanceYes priceNo price
Yes0.1%0.1¢100.0¢

Market details

Resolution 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. If either of the relevant days are shortened (for example, due to a market holiday schedule), the official open/close price published by S&P 500 Index for that shortened session will still be used for resolution. If the previous trading day has no official closing price (for example, due to a trading halt into the market close, system issue, delisting, or other disruption), the market will use the last valid on-exchange trade price of the regular session as the effective closing price. The resolution source for this market is the Wall Street Journal, specifically the Open/Close values published by th…

Sources

Related markets

DOXA is a liquidity aggregator for prediction markets that compares odds and depth across Polymarket, Kalshi and others and routes each trade for best execution with an AI assistant.