{"_meta":{"attribution":"Data aggregated by pdata.world (https://pdata.world) from 8 prediction-market venues; CC BY 4.0; source data © each venue.","canonical_url":"https://pdata.world/events/polymarket/1258858","as_of":"2026-10-27T15:23:02.101616Z","docs":"https://api.pdata.world/docs","cite_as":"According to pdata.world (tracking Polymarket): \"S&P 500 (SPX) Opens Up or Down on October 27?\" — 100% as of 2026-10-27 UTC. https://pdata.world/events/polymarket/1258858","source_url":"https://polymarket.com/event/spx-opens-up-or-down-on-october-27-2026"},"source":"polymarket","id":"1258858","ticker":"spx-opens-up-or-down-on-october-27-2026","slug":"spx-opens-up-or-down-on-october-27-2026","title":"S&P 500 (SPX) Opens Up or Down on October 27?","description":"This market will resolve to \"Up\" if the official S&P 500 Index open price for S&P 500 (SPX) on October 27 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 October 27 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":"2026-10-26T12:00:58Z","end_date":"2026-10-27T20:00:00Z","closed_time":null,"volume":5412.037611999999,"volume_24hr":5412.037612,"volume_24h_change":null,"normalized_vol_24hr":24.900657653808594,"normalized_volume":16.782636642456055,"liquidity":31260.00322,"open_interest":3115.609282,"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":0.4345000000000001,"top_outcome_volume_24h_change":5412.037612,"updated_at":"2026-10-27T15:05:50.291820Z","fetched_at":"2026-10-27T15:05:50.291820Z","added_at":"2026-10-26T12:22:50.427206Z","url":"https://polymarket.com/event/spx-opens-up-or-down-on-october-27-2026","chart_24h":[0.0,0.0,0.0,0.0,0.0,0.0,68.0,68.0,108.0,151.82,151.82,151.82,232.82,262.82,264.671852,365.596294,382.596294,392.596294,537.019996,593.0899959999999,950.677596,1612.947596,3334.436946,5412.037612,5412.037612],"kind":"live","mutually_exclusive":false,"markets_total":1,"markets":[{"source":"polymarket","id":"6248166","event_id":"1258858","slug":"spx-opens-up-or-down-on-october-27-2026","question":"S&P 500 (SPX) Opens Up or Down on October 27?","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 October 27 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 October 27 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":"2026-10-26T12:00:58Z","end_date":"2026-10-27T20:00:00Z","closed_time":null,"result":null,"volume":5412.037611999999,"volume_24hr":5412.037612,"prob_24h_change":0.4345000000000001,"volume_24h_change":5412.037612,"normalized_vol_24hr":29.992645263671875,"normalized_volume":21.681941986083984,"liquidity":31260.00322,"categories":["Finance"],"countries":[],"updated_at":"2026-10-27T15:05:50.467110Z","fetched_at":"2026-10-27T15:05:50.467110Z","added_at":"2026-10-26T12:22:50.548842Z","url":"https://polymarket.com/event/spx-opens-up-or-down-on-october-27-2026/spx-opens-up-or-down-on-october-27-2026","event_title":"S&P 500 (SPX) Opens Up or Down on October 27?","chart_24h":[0.565,0.5,0.53,0.605,0.59,0.75,0.73,0.5,0.495,0.65,0.645,0.64,0.6,0.46,0.335,0.435,0.57,0.6,0.74,0.86,0.955,0.9935,0.9995,0.9995]}]}