{"source":"polymarket","id":"953221","ticker":"spx-opens-up-or-down-on-september-3-2026","slug":"spx-opens-up-or-down-on-september-3-2026","title":"S&P 500 (SPX) Opens Up or Down on September 3?","description":"This market will resolve to \"Up\" if the official S&P 500 Index open price for S&P 500 (SPX) on September 3 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 3 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":"2026-09-02T12:01:02Z","end_date":"2026-09-03T20:00:00Z","closed_time":null,"volume":4487.202032,"volume_24hr":4487.202032,"volume_24h_change":null,"normalized_vol_24hr":26.936120986938477,"normalized_volume":16.092214584350586,"liquidity":769.6847,"open_interest":2019.300069,"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":0.49,"top_outcome_prob_24h_change":0.010000000000000009,"top_outcome_volume_24h_change":4487.202032,"updated_at":"2026-09-03T12:17:28.912817Z","fetched_at":"2026-09-03T12:17:28.912817Z","added_at":"2026-09-02T12:21:02.696549Z","url":"https://polymarket.com/event/spx-opens-up-or-down-on-september-3-2026","chart_24h":[0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,90.39,501.876606,513.291699,654.64763,864.7957769999999,866.7188519999999,876.7188519999999,891.7188519999999,1146.698852,1186.698852,1202.698852,1428.455716,1430.539048,1466.539048,1611.159048,1773.989361,2021.406147,2260.0163199999997,2328.639268,4427.202032],"kind":"live","markets":[{"source":"polymarket","id":"4126041","event_id":"953221","slug":"spx-opens-up-or-down-on-september-3-2026","question":"S&P 500 (SPX) Opens Up or Down on September 3?","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 3 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 3 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":[0.49,0.51],"probability":0.49,"spread":0.04,"active":true,"closed":false,"start_date":"2026-09-02T12:01:02Z","end_date":"2026-09-03T20:00:00Z","closed_time":null,"volume":4487.202032,"volume_24hr":4487.202032,"prob_24h_change":0.010000000000000009,"volume_24h_change":4487.202032,"normalized_vol_24hr":30.22486114501953,"normalized_volume":20.74714469909668,"liquidity":748.8691,"categories":["Finance"],"countries":[],"updated_at":"2026-09-03T12:17:29.599947Z","fetched_at":"2026-09-03T12:17:29.599947Z","added_at":"2026-09-02T12:21:02.822769Z","url":"https://polymarket.com/event/spx-opens-up-or-down-on-september-3-2026/spx-opens-up-or-down-on-september-3-2026","event_title":"S&P 500 (SPX) Opens Up or Down on September 3?","chart_24h":[0.48,0.585,0.585,0.585,0.585,0.55,0.525,0.515,0.535,0.69,0.47,0.545,0.535,0.565,0.64,0.625,0.31,0.53,0.455,0.49,0.675,0.635,0.585,0.385,0.5,0.365]}],"_meta":{"attribution":"pdata.world — aggregated prediction-market data across 8 platforms","canonical_url":"https://pdata.world/events/polymarket/953221","as_of":"2026-09-03T12:29:11.637948Z","docs":"https://api.pdata.world/docs","cite_as":"According to pdata.world (tracking Polymarket): \"S&P 500 (SPX) Opens Up or Down on September 3?\" — top market at 49% probability across 1 outcome","source_url":null}}