S&P 500 (SPX) Opens Up or Down on April 21?

YES price

100¢

per share

NO price

per share

$199K 24h volume$298K liquidity$200K total volumeResolves April 21, 2026

About this market

This market will resolve to "Up" if the official S&P 500 Index open price for S&P 500 (SPX) on April 21 is higher than the official S&P 500 Index closing price for SPX on the most recent prior trading day. This market will resolve to "Down" if the official S&P 500 Index open price for S&P 500 (SPX) on April 21 is lower than the official S&P 500 Index closing price for SPX on the most recent prior trading day. E.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. If 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. If SPX does not trade at all during the regular session, the market will resolve 50-50. If 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. If 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. The resolution source for this market is the Wall Street Journal, specifically the Open/Close values published by the WSJ under "Historical Prices". US: https://www.wsj.com/market-data/stocks EMEA: https://www.wsj.com/market-data/stocks/emea ASIA: https://www.wsj.com/market-data/stocks/asia

AI Consensus Analysis

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How Clairvoyant analyzes this market

Three AI agents — Claude (Anthropic), Gemini (Google DeepMind), and Grok (xAI) — independently score this market using real-time web data and historical base rates. Their probability estimates are weighted by a proprietary accuracy model and combined into a consensus probability.

When the consensus diverges from the current market price by more than a minimum threshold, it surfaces as a trade opportunity. Kelly Criterion then sizes the position based on the magnitude of the edge — larger gaps produce larger positions, within hard portfolio caps.

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