{"source":"polymarket","id":"1118856","ticker":"spx-opens-up-or-down-on-october-5-2026","slug":"spx-opens-up-or-down-on-october-5-2026","title":"S&P 500 (SPX) Opens Up or Down on October 5?","description":"This market will resolve to \"Up\" if the official S&P 500 Index open price for S&P 500 (SPX) on October 5 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 5 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":"2026-10-02T12:14:38Z","end_date":"2026-10-05T20:00:00Z","closed_time":null,"volume":2856.82497,"volume_24hr":2856.82497,"volume_24h_change":null,"normalized_vol_24hr":23.748882293701172,"normalized_volume":14.39277458190918,"liquidity":441.7208,"open_interest":2086.933039,"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":0.43,"top_outcome_prob_24h_change":-0.12000000000000005,"top_outcome_volume_24h_change":2856.82497,"updated_at":"2026-10-05T04:36:30.864850Z","fetched_at":"2026-10-05T04:36:30.864850Z","added_at":"2026-10-02T12:24:29.491893Z","url":"https://polymarket.com/event/spx-opens-up-or-down-on-october-5-2026","chart_24h":[0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,20.0,120.0,140.0,140.0,140.0,140.0,450.227273,739.366398,1149.42497,2499.38497,2659.71497,2856.82497],"kind":"live","markets":[{"source":"polymarket","id":"5203044","event_id":"1118856","slug":"spx-opens-up-or-down-on-october-5-2026","question":"S&P 500 (SPX) Opens Up or Down on October 5?","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 5 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 5 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":[0.43,0.57],"probability":0.43,"spread":0.02,"active":true,"closed":false,"start_date":"2026-10-02T12:14:38Z","end_date":"2026-10-05T20:00:00Z","closed_time":null,"volume":2856.82497,"volume_24hr":2856.82497,"prob_24h_change":-0.12000000000000005,"volume_24h_change":2856.82497,"normalized_vol_24hr":25.08642578125,"normalized_volume":18.5795841217041,"liquidity":612.4812,"categories":["Finance"],"countries":[],"updated_at":"2026-10-05T04:36:31.161490Z","fetched_at":"2026-10-05T04:36:31.161490Z","added_at":"2026-10-02T12:24:29.753579Z","url":"https://polymarket.com/event/spx-opens-up-or-down-on-october-5-2026/spx-opens-up-or-down-on-october-5-2026","event_title":"S&P 500 (SPX) Opens Up or Down on October 5?","chart_24h":[0.55,0.555,0.555,0.555,0.61,0.665,0.605,0.645,0.66,0.74,0.725,0.535,0.43]}],"_meta":{"attribution":"pdata.world — aggregated prediction-market data across 8 platforms","canonical_url":"https://pdata.world/events/polymarket/1118856","as_of":"2026-10-05T04:55:39.887672Z","docs":"https://api.pdata.world/docs","cite_as":"According to pdata.world (tracking Polymarket): \"S&P 500 (SPX) Opens Up or Down on October 5?\" — top market at 43% probability across 1 outcome","source_url":null}}