{"source":"polymarket","id":"772152","ticker":"spx-opens-up-or-down-on-july-31-2026","slug":"spx-opens-up-or-down-on-july-31-2026","title":"S&P 500 (SPX) Opens Up or Down on July 31?","description":"This market will resolve to \"Up\" if the official S&P 500 Index open price for S&P 500 (SPX) on July 31 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 July 31 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":"2026-07-30T12:00:14Z","end_date":"2026-07-31T20:00:00Z","closed_time":null,"volume":3101.087226,"volume_24hr":3101.087226,"volume_24h_change":null,"normalized_vol_24hr":23.56009292602539,"normalized_volume":14.73273754119873,"liquidity":2472.9417,"open_interest":2692.452016,"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":0.96,"top_outcome_prob_24h_change":0.45499999999999996,"top_outcome_volume_24h_change":3101.087226,"updated_at":"2026-07-31T09:27:03.112234Z","fetched_at":"2026-07-31T09:27:03.112234Z","added_at":"2026-07-30T12:56:21.457901Z","url":"https://polymarket.com/event/spx-opens-up-or-down-on-july-31-2026","chart_24h":[0.0,0.0,0.0,0.0,1.81818,1.81818,1.81818,1.81818,1.81818,1.81818,1.81818,5.32818,5.32818,35.32818,81.229861,787.1785949999999,919.803595,919.803595,1425.0402789999998,2714.2387009999998,2961.2387009999998,3101.087226,3101.087226],"markets":[{"source":"polymarket","id":"3220722","event_id":"772152","slug":"spx-opens-up-or-down-on-july-31-2026","question":"S&P 500 (SPX) Opens Up or Down on July 31?","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 July 31 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 July 31 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":[0.96,0.04],"probability":0.96,"spread":0.02,"active":true,"closed":false,"start_date":"2026-07-30T12:00:14Z","end_date":"2026-07-31T20:00:00Z","closed_time":null,"volume":3101.087226,"volume_24hr":3101.087226,"prob_24h_change":0.45499999999999996,"volume_24h_change":3101.087226,"normalized_vol_24hr":29.12933921813965,"normalized_volume":18.96452522277832,"liquidity":2550.062,"categories":["Finance"],"countries":[],"updated_at":"2026-07-31T09:28:08.192855Z","fetched_at":"2026-07-31T09:27:03.734411Z","added_at":"2026-07-30T12:56:21.586187Z","url":"https://polymarket.com/event/spx-opens-up-or-down-on-july-31-2026/spx-opens-up-or-down-on-july-31-2026","event_title":"S&P 500 (SPX) Opens Up or Down on July 31?","chart_24h":[0.505,0.505,0.54,0.51,0.51,0.505,0.515,0.53,0.5,0.51,0.505,0.695,0.64,0.64,0.6,0.775,0.845,0.9,0.9,0.875,0.915,0.94,0.96]}],"_meta":{"attribution":"pdata.world — aggregated prediction-market data across 8 platforms","canonical_url":"https://pdata.world/events/polymarket/772152","as_of":"2026-07-31T09:40:27.448519Z","docs":"https://api.pdata.world/docs","cite_as":"According to pdata.world (tracking Polymarket): \"S&P 500 (SPX) Opens Up or Down on July 31?\" — top market at 96% probability across 1 outcome","source_url":null}}