TOTAL VOLUME:
$61.8b
24H VOL:
$244,265,276
24H TRANSACTIONS:
600,069,390
OPEN INTEREST:
$1,349,697,137
578,254
Markets across
14,382
events
MATCHED EVENTS:
4,099
PLATFORM COVERAGE:
4
Polymarket:
50%
VS.
Kalshi:
50%
S&P 500 (SPX) Up or Down on March 9? Odds & Prediction Markets
Volume:
$523,497
S&P 500 (SPX) Up or Down on March 9? 100%
6,725 or above 100%
6,700 or above 100%
Closed: Mar 9, 4:00 PM EST
Polymarket
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 9, 2026 compared to the prior trading day. Polymarket uses a relative day-over-day comparison, while Kalshi uses absolute price thresholds. Both markets reference the official closing price for that date.
PredictionHero - Resolution Divergence Alerts (RDA)
Divergence Detected
Issue:
Polymarket uses relative day-over-day price comparison logic, while Kalshi uses 50 distinct absolute price thresholds. The two platforms are measuring fundamentally different outcomes and cannot be reconciled into a single unified resolution.Hero Tip:
Treat these as two separate markets. Polymarket requires knowledge of March 8, 2026 close (or prior trading day if March 8 is a holiday). Kalshi requires identifying your specific threshold contract and comparing March 9 close against that single level. Cross-platform arbitrage is not viable here due to structural incompatibility.Critical Divergence Points:
Polymarket:
Relative movement market. Resolves Up if March 9 close > prior trading day close; Down if lower; 50-50 if equal. Uses WSJ Historical Prices as official source. Handles shortened sessions and trading halts with fallback to last valid on-exchange trade price.Kalshi:
Absolute threshold market with 50 separate Yes conditions, each tied to a different price level (6074.9999 to 7549.9999). No explicit No condition stated; implicit No would be if close is at or below the lowest applicable threshold. Does not reference prior-day close or relative movement.
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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