As of today the market prices S&P 500 (SPX) Up or Down on September 11 at 93% — that is what traders are paying, in real money, for a share that pays $1.00 if it happens.
This market will resolve to "Up" if the official S&P 500 Index closing price for S&P 500 (SPX) on Friday, September 11, 2026 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 closing price for S&P 500 (SPX) on Friday, September 11, 2026 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 specified closing 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 closing price published by S&P 500 Index for that shortened session will still be used for resolution.
If either of the relevant days have 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 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
Frequently Asked Questions
What are the current odds for S&P 500 (SPX) Up or Down on September 11??
The market currently prices this at 93% (93¢ per share). Odds update continuously as traders buy and sell on Polymarket.
Will S&P 500 (SPX) Up or Down on September 11?
S&P 500 (SPX) Up or Down on September 11? is the market favorite at 93%, based on real money wagered by traders who have moved $119K through this market. Prediction-market odds have historically tracked outcomes more closely than polls, but they are a forecast, not a guarantee.
How much money is on S&P 500 (SPX) Up or Down on September 11??
$119K has been traded on this market in total, including $119K in the last 24 hours, with $7K of resting liquidity in the order book.
When does S&P 500 (SPX) Up or Down on September 11? resolve?
This market is scheduled to resolve on September 11, 2026. Winning shares pay out $1.00 each; losing shares expire worthless.
How does S&P 500 (SPX) Up or Down on September 11? resolve?
This market will resolve to "Up" if the official S&P 500 Index closing price for S&P 500 (SPX) on Friday, September 11, 2026 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 closing price for S&P 500 (SPX) on Friday, September 11, 2026 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 spe
Where can I bet on S&P 500 (SPX) Up or Down on September 11?
This is a Polymarket prediction market — you trade YES/NO shares against other users rather than against a bookmaker. Polynter.net tracks the odds, volume and trader activity; trading itself happens on Polymarket.