{"source":"polymarket","id":"958882","ticker":"spx-opens-up-or-down-on-september-4-2026","slug":"spx-opens-up-or-down-on-september-4-2026","title":"S&P 500 (SPX) Opens Up or Down on September 4?","description":"This market will resolve to \"Up\" if the official S&P 500 Index open price for S&P 500 (SPX) on September 4 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 September 4 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":"2026-09-03T12:01:03Z","end_date":"2026-09-04T20:00:00Z","closed_time":null,"volume":39864.87490699999,"volume_24hr":39754.874907,"volume_24h_change":null,"normalized_vol_24hr":43.17092514038086,"normalized_volume":25.53534698486328,"liquidity":27308.27562,"open_interest":33763.285753,"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":0.9995,"top_outcome_prob_24h_change":0.4145000000000001,"top_outcome_volume_24h_change":39644.874907,"updated_at":"2026-09-04T14:19:20.347455Z","fetched_at":"2026-09-04T14:19:20.347455Z","added_at":"2026-09-03T12:18:41.856349Z","url":"https://polymarket.com/event/spx-opens-up-or-down-on-september-4-2026","chart_24h":[110.0,110.0,120.0,120.0,120.0,120.0,120.0,120.0,121.886791,127.547167,247.547167,347.547167,347.547167,347.547167,700.228734,797.971071,1145.000207,1195.134821,1564.104821,1960.176248,1961.395759,1966.395759,1967.630325,1967.630325,2061.8762,2061.8762,2075.2095320000003,2087.7095320000003,2148.9439070000003,2161.4439070000003,2196.4439070000003,2274.984955,2612.174955,2752.799955,3594.288403,8516.392611,39754.874907],"kind":"live","markets":[{"source":"polymarket","id":"4187284","event_id":"958882","slug":"spx-opens-up-or-down-on-september-4-2026","question":"S&P 500 (SPX) Opens Up or Down on September 4?","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 September 4 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 September 4 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":[0.9995,0.0005],"probability":0.9995,"spread":0.001,"active":true,"closed":false,"start_date":"2026-09-03T12:01:03Z","end_date":"2026-09-04T20:00:00Z","closed_time":null,"volume":39864.87490699998,"volume_24hr":39754.874907,"prob_24h_change":0.4145000000000001,"volume_24h_change":39644.874907,"normalized_vol_24hr":46.999874114990234,"normalized_volume":32.923709869384766,"liquidity":27308.27562,"categories":["Finance"],"countries":[],"updated_at":"2026-09-04T14:19:20.761640Z","fetched_at":"2026-09-04T14:19:20.761640Z","added_at":"2026-09-03T12:18:42.584796Z","url":"https://polymarket.com/event/spx-opens-up-or-down-on-september-4-2026/spx-opens-up-or-down-on-september-4-2026","event_title":"S&P 500 (SPX) Opens Up or Down on September 4?","chart_24h":[0.585,0.585,0.5,0.5,0.535,0.5,0.48,0.51,0.51,0.515,0.505,0.505,0.505,0.515,0.515,0.56,0.64,0.665,0.685,0.665,0.645,0.625,0.545,0.57,0.605,0.625,0.615,0.555,0.615,0.66,0.685,0.535,0.0095,0.9995]}],"_meta":{"attribution":"pdata.world — aggregated prediction-market data across 8 platforms","canonical_url":"https://pdata.world/events/polymarket/958882","as_of":"2026-09-04T14:30:18.153773Z","docs":"https://api.pdata.world/docs","cite_as":"According to pdata.world (tracking Polymarket): \"S&P 500 (SPX) Opens Up or Down on September 4?\" — top market at 100% probability across 1 outcome","source_url":null}}