TOTAL VOLUME:

$54.4b

24H VOL:

$216,099,358

OPEN INTEREST:

$1,189,677,720

500,754

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13,672

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MATCHED EVENTS:

1,801

PLATFORM COVERAGE:

4

Polymarket:

51%

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Kalshi:

49%

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Trending

S&P 500 (SPX) Up or Down on April 27?

Volume:
$359,741
Outcome
Chance %
Price
Liquidity
Volume
24h
7d
Open Interest
Ends in
Result
Trade

Description

This market will resolve to "Up" if the official S&P 500 Index closing price for S&P 500 (SPX) on Monday, April 27, 2026 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 closing price for S&P 500 (SPX) on Monday, April 27, 2026 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 specified closing 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 closing price published by S&P 500 Index for that shortened session will still be used for resolution. If either of the relevant days have 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 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

PredictionHero - Resolution Divergence Alerts (RDA)

Unified Resolution Criteria (Consistent across platforms)

Both platforms employ identical binary comparison logic (Up vs Down) against the same official data source (WSJ), with harmonized edge-case handling.

Primary resolution logic:

Wall Street Journal Historical Prices (Close values). Regional variants available at https://www.wsj.com/market-data/stocks, https://www.wsj.com/market-data/stocks/emea, and https://www.wsj.com/market-data/stocks/asia

Core resolution logic:

  • Resolves UP if April 27, 2026 SPX closing price is strictly higher than the most recent prior trading day closing price
  • Resolves DOWN if April 27, 2026 SPX closing price is strictly lower than the most recent prior trading day closing price
  • Prior trading day is ordinarily the immediately preceding calendar day (e.g., Friday for Monday resolution), unless that day was a market holiday, in which case the next most recent trading day is used
  • All prices rounded to nearest cent using standard rounding rules
  • Resolves 50-50 if closing prices are exactly equal after rounding
  • Resolves 50-50 if SPX does not trade during regular session on April 27, 2026

Edge cases & Clarifications:

  • Shortened Trading Session: If either April 27 or the prior trading day is a shortened session (e.g., day before Thanksgiving), the official closing price published by S&P 500 Index for that shortened session is used for resolution
  • No Official Closing Price: If either relevant day has no official closing price due to trading halt, system issue, delisting, or other disruption, the last valid on-exchange trade price of the regular session is used as the effective closing price
  • Exact Price Tie: If the two closing prices are exactly equal after rounding to the nearest cent, the market resolves 50-50
  • No Trading Activity: If SPX does not trade at all during the regular session on April 27, 2026, the market resolves 50-50
  • Prior Trading Day Determination: The most recent prior trading day is determined by working backward from April 27, 2026 to the most recent day the market was open, accounting for weekends and US market holidays

Timing:

Resolution occurs after market close on April 27, 2026 (or the next business day if April 27 is not a trading day) once official closing prices are published by the Wall Street Journal
Our PredictionHero Resolution Divergence Alerts (RDA) are there to help users identify potential differences across platforms. They do not replace or supersede the official rules and description of any prediction market. Users are solely responsible for reviewing and understanding the applicable rules and resolution criteria before placing any trade or bet. If you notice a potential inconsistency, discrepancy, or error in an alert, please report it to our team so we can review and improve the accuracy of our data.

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PredictionHero © 2026 · v0.13.0PredictionHero provides aggregated market data and informational signals only. Nothing on this site constitutes financial, legal, or investment advice. Markets are volatile and speculative. Past performance does not guarantee future results. Always do your own research and consult qualified professionals before making decisions involving risk.