TOTAL VOLUME:
$54.4b
24H VOL:
$218,201,443
24H TRANSACTIONS:
527,797,601
OPEN INTEREST:
$1,191,873,651
500,842
Markets across
13,663
events
MATCHED EVENTS:
1,809
PLATFORM COVERAGE:
4
Polymarket:
51%
VS.
Kalshi:
49%
S&P 500 (SPX) Up or Down on March 12?
Volume:
$37,193
Outcome
Chance %
Price
Liquidity
Volume
24h
7d
Open Interest
Ends in
Result
Trade
Description
This event group tracks whether the S&P 500 Index closes higher or lower on March 12, 2026 compared to the prior trading day. Polymarket resolves based on directional price movement (Up/Down/Tie), while Kalshi offers 60 separate binary contracts each tied to specific price thresholds. The two platforms use fundamentally different resolution architectures despite referencing the same underlying asset and date.
PredictionHero - Resolution Divergence Alerts (RDA)
Divergence Detected
Issue:
Polymarket uses relative directional resolution (vs. prior close) while Kalshi uses absolute threshold-based resolution (60 separate binary contracts). These represent incompatible market architectures for the same underlying event, creating basis risk and preventing direct arbitrage.Hero Tip:
Treat these as two separate market families, not as redundant coverage of the same outcome. Polymarket is a directional bet; Kalshi contracts are level-based bets. Your trading strategy must account for this structural difference. Additionally, Kalshi does not specify its official price source, while Polymarket explicitly uses WSJ Historical Prices—verify Kalshi's source before settlement.Critical Divergence Points:
- Polymarket: Directional relative comparison market. Resolves Up if March 12, 2026 SPX close exceeds the most recent prior trading day close; Down if lower; 50-50 if equal or no regular session trade. Uses WSJ Historical Prices (Close values) as official source. Handles shortened sessions and trading halts by using last valid on-exchange trade price if no official close exists.
- Kalshi: 60 separate binary threshold contracts, each resolving Yes if end-of-day SPX on March 12, 2026 exceeds a specific absolute price level (6024.9999 through 7499.9999 in 25-point increments). No relative comparison logic; no tie resolution; no explicit resolution source specified. All 60 conditions are independent Yes/No outcomes.
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.