TOTAL VOLUME:
$54.3b
24H VOL:
$198,896,558
OPEN INTEREST:
$1,191,591,877
500,572
Markets across
13,691
events
MATCHED EVENTS:
1,797
PLATFORM COVERAGE:
4
Polymarket:
51%
VS.
Kalshi:
49%
S&P 500 (SPX) Up or Down on April 6?
Description
This market will resolve to "Up" if the official S&P 500 Index closing price for S&P 500 (SPX) on Monday, April 6, 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 6, 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)
Divergence Detected
Issue:
Polymarket and Kalshi use fundamentally incompatible resolution frameworks. Polymarket resolves based on directional price movement (Up/Down relative to prior trading day), while Kalshi resolves based on absolute index level thresholds (52 separate price-level conditions). These markets cannot produce equivalent outcomes.Hero Tip:
Do not assume these markets are equivalent. Polymarket's 'Up' outcome depends entirely on the prior day's close (unknown until April 5), while Kalshi's outcomes are fixed absolute levels. A market that is 'Up' on Polymarket could resolve to multiple different Kalshi outcomes simultaneously, or vice versa. Verify which platform's logic matches your trading thesis before committing capital.Critical Divergence Points:
- Polymarket: Distinct stance: Resolves based on directional comparison between April 6 closing price and the most recent prior trading day's closing price. 'Up' if April 6 close is higher, 'Down' if lower, 50-50 if equal. Source: Wall Street Journal Historical Prices Close values. Quote: 'This market will resolve to Up if the official S&P 500 Index closing price for S&P 500 (SPX) on Monday, April 6, 2026 is higher than the official S&P 500 Index closing price for SPX on the most recent prior trading day.'
- Kalshi: Distinct stance: Resolves to Yes based on 52 independent absolute price-level thresholds ranging from 5824.9999 to 7299.9999. Each condition is a separate binary outcome (if April 6 close exceeds threshold X, resolve Yes). No directional comparison; no reference to prior trading day. Quote: 'If the end-of-day S&P 500 index value on April 06, 2026 is above 5824.9999, then the market resolves to Yes' (and 51 similar conditions at different levels).
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