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%
What will S&P 500 (SPX) close at in March?
Volume:
$239,113
Outcome
Chance %
Price
Liquidity
Volume
24h
7d
Open Interest
Ends in
Result
Trade
Description
This event group tracks the S&P 500 (SPX) closing price on the final trading day of March 2026. Polymarket offers 12 bracket-based binary markets covering price ranges from below $6,400 to above $7,300, while Kalshi provides 60 binary YES/NO markets with specific price thresholds. Both platforms resolve based on the official closing price for that date.
PredictionHero - Resolution Divergence Alerts (RDA)
Divergence Detected
Issue:
Polymarket uses mutually exclusive bracket ranges while Kalshi uses cumulative threshold logic. Both reference the same underlying settlement value (SPX close on final March 2026 trading day) but structure resolution incompatibly, creating different YES/NO outcome distributions.Hero Tip:
Polymarket markets are zero-sum within the bracket set (exactly one resolves YES). Kalshi markets are independent (multiple can resolve YES). When comparing prices across platforms, convert Kalshi thresholds to implied bracket probabilities. For example, if Kalshi shows high probability for 'above 6,499.9999', that corresponds to Polymarket's $6,500+ brackets combined.Critical Divergence Points:
- Polymarket: 12 mutually exclusive bracket-based markets covering $6,400 to $7,300+. Each bracket is 100-point wide (e.g., $6,400-$6,500, $6,500-$6,600). Tie-breaking rule: if price falls exactly between brackets, resolves to the higher bracket. Resolution source: Yahoo Finance SPX historical close prices at https://finance.yahoo.com/quote/%5EGSPC/history. Fallback: if no official close published, uses last valid recorded price in March.
- Kalshi: 60 independent YES/NO threshold markets with prices ranging from 5,599.9999 to 7,074.9999 in irregular increments. Each market resolves YES if end-of-day SPX on March 31, 2026 exceeds its specific threshold. Multiple markets can resolve YES simultaneously. No explicit fallback or tie-breaking rules stated; assumes official closing price is available.
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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