TOTAL VOLUME:
$97.2b
24H VOL:
$205,769,171
24H TRANSACTIONS:
950,106,883
OPEN INTEREST:
$2,078,492,000
827,238
Markets across
14,795
events
MATCHED EVENTS:
884
PLATFORM COVERAGE:
5
Polymarket:
45%
VS.
Kalshi:
55%
S&P close price end of 2026? Odds & Prediction Markets
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6,500-7,000
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$20
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Trade on Opinion
At 50.7¢ buys you 197 shares | Odds: 45% Total Payout: $197 | Net Profit: $97 Multiplier: 1.97x | ROI: 97% | APY: 319% 167 days to resolutionTrade on Polymarket
At 12¢ buys you 833 shares | Odds: 11% Total Payout: $833 | Net Profit: $733 Multiplier: 8.33x | ROI: 733% High Projected APY: 9,913% Low liquidity 168 days to resolutionDescription
This event group aggregates prediction markets across three platforms asking where the S&P 500 (SPX) will close on the final trading day of December 2026. All platforms use the same resolution date (December 31, 2026, or the final trading day if shortened) and the same official closing price source (Yahoo Finance), but differ significantly in their bracket definitions and logical coverage.
PredictionHero - Resolution Divergence Alerts (RDA)
Divergence Detected
Issue: Kalshi's resolution logic is internally contradictory and incomplete: it defines 27 overlapping conditions that all resolve to Yes, with no explicit No-resolution outcome, making the market logically unresolvable. Polymarket and Opinion use clean, mutually exclusive bracket logic with explicit tie-breaking, but cover a narrower price range (6000-8000+ only) compared to Kalshi's 4000-9000+ scope.Hero tip: Kalshi's market is fundamentally broken—avoid trading it until the platform clarifies the No-resolution threshold. Polymarket and Opinion are safe to trade but only cover 6000-8000+ ranges; prices outside this band cannot be resolved on those platforms. If you expect SPX to close below 6000 or above 8000, Kalshi is your only option, but demand written clarification on when it resolves No.Critical divergence points:
- Kalshi: Defines 27 overlapping Yes-resolution conditions covering ranges from 4000 to 9000+. All conditions resolve to Yes; no explicit No outcome is defined. Conditions include: above 9000 (Yes), below 4000 (Yes), 8800-9000 (Yes), 8600-8799.99 (Yes), 8400-8599.99 (Yes), 8200-8399.99 (Yes), 8000-8199.99 (Yes), 7800-7999.99 (Yes), 7600-7799.99 (Yes), 7400-7599.99 (Yes), 7200-7399.99 (Yes), 7000-7199.99 (Yes), 6800-6999.99 (Yes), 6600-6799.99 (Yes), 6400-6599.99 (Yes), 6200-6399.99 (Yes), 6000-6199.99 (Yes), 5800-5999.99 (Yes), 5600-5799.99 (Yes), 5400-5599.99 (Yes), 5200-5399.99 (Yes), 5000-5199.99 (Yes), 4800-4999.99 (Yes), 4600-4799.99 (Yes), 4400-4599.99 (Yes), 4200-4399.99 (Yes), 4000-4199.99 (Yes). Key Quote: 'If the S&P 500 index value on Dec 31, 2026 at 4pm EST is above 9000, then the market resolves to Yes' and 26 identical Yes conditions. Logical flaw: no explicit No outcome; market is unresolvable if SPX closes in any of these ranges (which is nearly all possible outcomes).
- Polymarket: Defines six mutually exclusive brackets: <6000 (Yes), 6000-6500 (Yes), 6500-7000 (Yes), 7000-7500 (Yes), 7500-8000 (Yes), >8000 (Yes). Each bracket resolves independently. Explicit tie-breaking rule: 'If the reported value falls exactly between two brackets, then this market will resolve to the higher range bracket.' Resolution source: Yahoo Finance historical close for final trading day of December 2026. Key Quote: 'This market will resolve according to the official closing price for S&P 500 (SPX) on the final trading day of December 2026.' Clean, non-overlapping logic; however, only covers 6000-8000+ range; prices below 6000 or above 8000 are not explicitly addressed in the bracket structure.
- Opinion: Defines six mutually exclusive brackets: <6000, 6000-6500, 6500-7000, 7000-7500, 7500-8000, >8000. Identical structure to Polymarket. No explicit tie-breaking rule stated, but implied to follow Polymarket's higher-bracket rule. Resolution source: Yahoo Finance (inferred from Polymarket alignment). Key Quote: Questions listed as '7000-7500', '6000-6500', '6500-7000', '>8000', '<6000', '7500-8000'. Clean, mutually exclusive logic; however, only covers 6000-8000+ range.
Polymarket
This market will resolve according to the official closing price for S&P 500 (SPX) on the final trading day of December 2026. If the reported value falls exactly between two brackets, then this market will resolve to the higher range bracket. If the final trading day of the month is shortened (for example, due to a market-holiday schedule), the official closing price published for that shortened session will still be used for resolution. If no official closing price is published for that session (for example, due to a trading halt into the 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 Yahoo Finance, specifically the S&P 500 (SPX) "Close" prices available at https://finance.yahoo.com/quote/%5EGSPC/history, published under "Historical Prices."
Kalshi
Resolution is determined by the S&P 500 index value on December 31, 2026 at 4pm EST. The event is divided into mutually exclusive price ranges, each representing a distinct outcome. The range containing the actual closing value resolves to Yes, while all others resolve to No. The market closes on December 31, 2026 and expires at the sooner of the first data release or one week after December 31, 2026. Per the Kalshi Rulebook, the Exchange has modified the Source Agency and Underlying for indices markets.
Opinion
This market will resolve according to the official closing price for S&P 500 (SPX) on the final trading day of December 2026. If the reported value falls exactly between two brackets, then this market will resolve to the higher range bracket. If the final trading day of the month is shortened (for example, due to a market-holiday schedule), the official closing price published for that shortened session will still be used for resolution. If no official closing price is published for that session (for example, due to a trading halt into the 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 Yahoo Finance, specifically the S&P 500 (SPX) "Close" prices available at https://finance.yahoo.com/quote/%5EGSPC/history, published under "Historical Prices."
Frequently asked questions
On Kalshi, the S&P 500 year-end 2026 close is priced as binary contracts tied to specific price thresholds. Polymarket and Kalshi can show different implied probabilities for the same outcome because of liquidity, fee structure, participant mix, and how each venue defines the contract. Traders buy or sell YES and NO shares based on whether they believe the index will close above or below defined strike levels by December 31, 2026. Each contract settles to 1.00 or 0.00 depending on the official closing price, and the market price reflects the collective probability assigned by active traders. Kalshi's order-book model allows precise entry and exit at any quoted spread.
The S&P 500 year-end 2026 market resolves on Dec 31, 2026, following the official close of regular trading hours on the final day of the year. The outcome is determined by the closing price of the S&P 500 index as reported by the exchange at market close. Once the official price is published, the contract settles according to the predetermined strike levels, and all positions are marked to their final value. Traders should verify the exact settlement time and data source with Polymarket before expiration.
Major catalysts for the S&P 500 through end of 2026 include Federal Reserve interest-rate decisions, inflation and employment data, corporate earnings revisions, geopolitical developments, and fiscal policy announcements. A sustained rise in real yields or recession signals could pressure equity valuations downward, while stronger-than-expected GDP growth or productivity gains could drive prices higher. Election outcomes, trade policy shifts, and central bank actions globally also influence capital flows into U.S. equities. Traders monitor these macro drivers continuously to adjust their positions on year-end price levels.
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