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 March 23?
Description
This market will resolve to "Up" if the official S&P 500 Index closing price for S&P 500 (SPX) on Monday, March 23, 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, March 23, 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 vs. prior trading day), while Kalshi contains 60 separate binary markets each tied to specific absolute price thresholds, creating a logical contradiction where Kalshi's conditions are mutually exclusive and collectively exhaustive in ways that cannot align with a single directional outcome.Hero Tip:
Do not assume these markets will settle identically. On Polymarket, you are betting on directional movement relative to March 22, 2026. On Kalshi, you are betting on whether SPX closes above specific absolute levels (ranging from 5849.9999 to 7324.9999). A single SPX close value will resolve Polymarket to one outcome (Up, Down, or 50-50) but will resolve ALL 60 Kalshi markets simultaneously based on threshold crossing. Arbitrage or hedge accordingly.Critical Divergence Points:
- Polymarket: Distinct stance: Resolves based on directional comparison between March 23, 2026 closing price and the most recent prior trading day closing price. 'This market will resolve to Up if the official S&P 500 Index closing price for S&P 500 (SPX) on Monday, March 23, 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 60 separate binary outcomes, each tied to whether the end-of-day SPX value on March 23, 2026 exceeds a specific absolute threshold (e.g., 5874.9999, 6974.9999, 7324.9999). 'If the end-of-day S&P 500 index value on March 23, 2026 is above [threshold], then the market resolves to Yes.'
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