{"source":"polymarket","id":"903973","ticker":"spx-opens-up-or-down-on-august-25-2026","slug":"spx-opens-up-or-down-on-august-25-2026","title":"S&P 500 (SPX) Opens Up or Down on August 25?","description":"This market will resolve to \"Up\" if the official S&P 500 Index open price for S&P 500 (SPX) on August 25 is higher than the official S&P 500 Index closing price for SPX on the most recent prior trading day.\n\nThis market will resolve to \"Down\" if the official S&P 500 Index open price for S&P 500 (SPX) on August 25 is lower than the official S&P 500 Index closing price for SPX on the most recent prior trading day.\n\nE.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.\n\nIf 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.\n\nIf SPX does not trade at all during the regular session, the market will resolve 50-50.\n\nIf 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.\n\nIf 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.\n\nThe resolution source for this market is the Wall Street Journal, specifically the Open/Close values published by the WSJ under \"Historical Prices\".\n\nUS: https://www.wsj.com/market-data/stocks\nEMEA: https://www.wsj.com/market-data/stocks/emea\nASIA: https://www.wsj.com/market-data/stocks/asia","image":"https://polymarket-upload.s3.us-east-2.amazonaws.com/s-and-p-500-1e40af6979.png","icon":"https://polymarket-upload.s3.us-east-2.amazonaws.com/s-and-p-500-1e40af6979.png","active":true,"closed":false,"start_date":"2026-08-24T12:20:01Z","end_date":"2026-08-25T20:00:00Z","closed_time":null,"volume":3779.8982369999994,"volume_24hr":3779.8982369999994,"volume_24h_change":null,"normalized_vol_24hr":28.218664169311523,"normalized_volume":15.447196960449219,"liquidity":1369.4681,"open_interest":4369.07621,"categories":["Finance"],"tags":[{"id":"102683","slug":"spx","label":"SPX"},{"id":"102127","slug":"up-or-down","label":"Up or Down"},{"id":"102281","slug":"daily","label":"Daily"},{"id":"102682","slug":"indicies","label":"Indicies"},{"id":"120","slug":"finance","label":"Finance"},{"id":"102169","slug":"hide-from-new","label":"Hide From New"}],"synthetic":false,"is_group":false,"group_key":null,"parent_event_id":null,"probability":null,"spread":null,"top_outcome":"","top_outcome_probability":0.815,"top_outcome_prob_24h_change":0.18499999999999994,"top_outcome_volume_24h_change":3779.8982369999994,"updated_at":"2026-08-25T04:51:12.148526Z","fetched_at":"2026-08-25T04:51:12.148526Z","added_at":"2026-08-24T12:51:23.922155Z","url":"https://polymarket.com/event/spx-opens-up-or-down-on-august-25-2026","chart_24h":[0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,25.0,314.109588,474.049588,474.049588,684.239588,808.085738,3568.998856,3568.998856,3596.0396709999995,3633.5768109999995,3779.8982369999994],"markets":[{"source":"polymarket","id":"3840813","event_id":"903973","slug":"spx-opens-up-or-down-on-august-25-2026","question":"S&P 500 (SPX) Opens Up or Down on August 25?","group_item_title":null,"description":"This market will resolve to \"Up\" if the official S&P 500 Index open price for S&P 500 (SPX) on August 25 is higher than the official S&P 500 Index closing price for SPX on the most recent prior trading day.\n\nThis market will resolve to \"Down\" if the official S&P 500 Index open price for S&P 500 (SPX) on August 25 is lower than the official S&P 500 Index closing price for SPX on the most recent prior trading day.\n\nE.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.\n\nIf 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.\n\nIf SPX does not trade at all during the regular session, the market will resolve 50-50.\n\nIf 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.\n\nIf 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.\n\nThe resolution source for this market is the Wall Street Journal, specifically the Open/Close values published by the WSJ under \"Historical Prices\".\n\nUS: https://www.wsj.com/market-data/stocks\nEMEA: https://www.wsj.com/market-data/stocks/emea\nASIA: https://www.wsj.com/market-data/stocks/asia","image":"https://polymarket-upload.s3.us-east-2.amazonaws.com/s-and-p-500-1e40af6979.png","icon":"https://polymarket-upload.s3.us-east-2.amazonaws.com/s-and-p-500-1e40af6979.png","outcomes":["Up","Down"],"outcome_prices":[0.815,0.185],"probability":0.815,"spread":0.25,"active":true,"closed":false,"start_date":"2026-08-24T12:20:01Z","end_date":"2026-08-25T20:00:00Z","closed_time":null,"volume":3779.8982369999994,"volume_24hr":3779.8982369999994,"prob_24h_change":0.18499999999999994,"volume_24h_change":3779.8982369999994,"normalized_vol_24hr":29.311452865600586,"normalized_volume":19.90957260131836,"liquidity":1355.0718,"categories":["Finance"],"countries":[],"updated_at":"2026-08-25T04:54:40.517632Z","fetched_at":"2026-08-25T04:51:12.319386Z","added_at":"2026-08-24T12:51:24.049644Z","url":"https://polymarket.com/event/spx-opens-up-or-down-on-august-25-2026/spx-opens-up-or-down-on-august-25-2026","event_title":"S&P 500 (SPX) Opens Up or Down on August 25?","chart_24h":[0.63,0.625,0.625,0.625,0.605,0.625,0.625,0.55,0.525,0.705,0.59,0.595,0.53,0.76,0.715,0.67,0.675,0.815]}],"_meta":{"attribution":"pdata.world — aggregated prediction-market data across 8 platforms","canonical_url":"https://pdata.world/events/polymarket/903973","as_of":"2026-08-25T04:59:40.302732Z","docs":"https://api.pdata.world/docs","cite_as":"According to pdata.world (tracking Polymarket): \"S&P 500 (SPX) Opens Up or Down on August 25?\" — top market at 82% probability across 1 outcome","source_url":null}}