This market will resolve to "Up" if the official S&P 500 Index open price for S&P 500 (SPX) on August 27 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 August 27 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 the WSJ under "Historical Prices".
US: https://www.wsj.com/market-data/stocks
EMEA: https://www.wsj.com/market-data/stocks/emea
ASIA: https://www.wsj.com/market-data/stocks/asia
Resolution Source: www.wsj.com
Odds & FAQ
What are the current odds for S&P 500 (SPX) Opens Up or Down on August 27?
At 89%, Up has pulled far clear of Down (11%). Prices stay live until resolution, but the market sees one clear outcome.
What do traders predict for S&P 500 (SPX) Opens Up or Down on August 27?
With 89% implied for Up, the market has largely made up its mind. Still a forecast, not a result: prices react instantly if the story changes.
When does the S&P 500 (SPX) Opens Up or Down on August 27 market resolve?
Mark 27 Aug 2026 (1 days left): that's when this market is due to resolve, following Polymarket's published criteria once the result is verified.
How much money is trading on S&P 500 (SPX) Opens Up or Down on August 27?
$10.5K in total volume has traded here. Deeper markets like this tend to price events more sharply.
How can I trade S&P 500 (SPX) Opens Up or Down on August 27 on Polymarket?
Track the live odds on this page, then open the market on Polymarket to take a position. Trade carefully - only stake what you can afford to lose.
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