SPY (SPY) Up or Down on May 18? Probability Surges 24% on Polymarket
Market probability for SPY (SPY) Up or Down on May 18 jumped 24.05% in the last hour, reaching 26.45%. Observe shifts ahead of the May 18th resolution.
Published Tue, 29 Sep 2026 13:05:33 GMT
The probability for SPY (SPY) Up or Down on May 18 has seen a significant movement. The market's current probability stands at 26.45%. Over the past hour (windowLabel: 1h), this probability has increased by 24.05 percentage points.
This surge indicates heightened interest or a shift in perceived likelihood regarding the SPY's movement by the resolution date of May 18, 2026. The market's current pricing suggests that a higher probability is now assigned to one of the potential outcomes compared to the previous hour.
What to Watch Next: Investors and observers should monitor further changes in the probability for this market. Consistent upward or downward trends in the probability could signal evolving sentiment. Key factors influencing such probabilities in prediction markets include shifts in underlying asset performance, news related to the S&P 500 index, and broader economic indicators.
Context on Prediction Markets: This market operates on Polymarket, a decentralized prediction market platform. The probability displayed (e.g., 26.45%) is derived from the trading activity of participants who buy and sell "Yes" or "No" shares representing the potential outcomes of the question. A probability of 26.45% implies that, based on current trading, the market collectively assigns a 26.45% chance to the "Yes" outcome (SPY Up) and a 73.55% chance to the "No" outcome (SPY Down) by the specified end date. These probabilities are dynamic and reflect the consensus of market participants in real-time.
The market resolves based on the official closing price of the SPY ETF on May 18, 2026. If the price is higher than the price on the day the market was created (or a specified reference price if applicable), the "Yes" shares pay out; otherwise, "No" shares pay out. The lack of data in stats.volume24h, stats.trades24h, and stats.whales24h suggests limited or no trading activity within the last 24 hours, making the recent `deltaPct` particularly notable as the primary indicator of recent price action within the market contract.
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Track this market live on Polydar →Frequently asked
- What does SPY (SPY) Up or Down on May 18 mean?
- This market resolves based on the price of the SPDR S&P 500 ETF Trust (SPY) on May 18, 2026. 'Up' typically means the SPY price is higher than a reference price, and 'Down' means it is lower.
- What caused the probability to increase by 24.05%?
- The increase represents a shift in trading activity on the prediction market. Participants buying 'Yes' shares or selling 'No' shares contributed to the rising probability for the 'Up' outcome.
- How are prediction market probabilities calculated?
- Probabilities are determined by the trading prices of shares in the market. If 'Yes' shares are trading at $0.2645, the market implies a 26.45% probability for that outcome.