Resolution criteria on PolyGram: This market will resolve to "Up" if the official S&P 500 Index open price for S&P 500 (SPX) on May 8 is higher than the official S&P 500 Index closing price for SPX on the most recent prior trading day. This market will resolve to "Down" if the official S&P 500 Index open price for S&P 500 (SPX) on May 8 is lower than the official S&P 500 Index closing price for SPX on the most recent prior trading day. E.g., ordinarily, a market on Monday would refer to the previous Friday for its most recent closing price, unless that Friday were a market holiday, in which case it would refer to Thursday, or the next most recent trading day.
PolyGram is an on-chain prediction market where you trade YES or NO outcome shares with real USDC on Polygon. For this market, buy YES if you believe the event will happen, or NO if you think it won't. Your maximum loss is your stake — winning shares pay $1.00 each at resolution. Unlike sportsbooks, there is no house edge: prices are set by supply and demand from other traders and reflect the crowd's real-time probability.
Market outcomes
| S&P 500 (SPX) Opens Up or Down on May 8? | 100% YES | 0% NO |
The S&P 500 will open on 8 May 2026 either above or below its prior trading day's close. This binary outcome—a gap up versus a gap down—depends on overnight price discovery across global markets and pre-market sentiment in the hours before the 9:30 ET opening bell. The current Polymarket order book is pricing this at 100% implied probability for an up opening, reflecting either extreme conviction among traders or insufficient liquidity to challenge the consensus.
Historically, S&P 500 gap outcomes cluster around 50–55% up days when examined across large sample sizes, though this varies by market regime. During periods of sustained rallies or risk-on sentiment, up gaps occur more frequently; during sell-offs or heightened uncertainty, down gaps predominate. The 100% probability here suggests traders are either pricing in a specific overnight catalyst expected to move markets higher, or the market is illiquid enough that early positions have gone unchallenged. Comparable single-day gap markets on major indices typically see probabilities ranging from 35% to 65% absent major scheduled events.
Traders should monitor earnings announcements, Federal Reserve communications, and economic data releases scheduled for 7 May or the evening of 8 May. Overnight developments in Asian and European markets on 7–8 May will establish the tone for the US open. Geopolitical events or central bank decisions can shift overnight sentiment materially. The settlement window closes at 20:00 ET on 8 May, allowing the official opening price to be confirmed before resolution.
This market settles from the official outcome published at https://www.wsj.com/market-data/stocks. A proposer submits the final result to the UMA optimistic oracle on Polygon; the two-hour dispute window closes and payouts clear in USDC.
The mechanics for trading "S&P 500 (SPX) Opens Up or Down on May 8?" are the same as any other PolyGram event contract. Each YES share resolves to $1 if the event happens, or $0 if it doesn't. The current price between 0¢ and 100¢ is the market's probability estimate, set live by the order book.
$178K in lifetime turnover and $0 of resting liquidity puts this market in the top 30% by volume for spx contracts on PolyGram. Order-book depth is thin — large orders may need to be split across the book or executed as limit orders.
Last 24 hours alone saw $154K in turnover, well above the lifetime daily-average for this market — a clear sign of news catalysing trader activity right now.
The market has been open for under a month — fresh enough that information asymmetry remains a real factor.
Higher-volume markets tend to have tighter spreads and faster price discovery — meaning the displayed YES/NO percentages are more likely to reflect the true crowd-implied probability rather than a single trader's directional view.
As of today, traders on Polymarket price this outcome at 100%. The number updates continuously as the order book clears. PolyGram mirrors the same live odds with locale-aware formatting and USDC settlement.
Resolution is sourced from https://www.wsj.com/market-data/stocks. Settlement is executed by the UMA optimistic oracle on Polygon, with a 2-hour dispute window before payouts clear.
This prediction market is scheduled to close on 8 May 2026. After the resolving event occurs, settlement typically clears within 24 hours once the UMA optimistic oracle confirms the outcome. All payouts are in USDC on the Polygon network.
To trade on this prediction market, create a free PolyGram account at polygram.ink, deposit USDC via Polygon, and place a YES or NO order on the outcome you believe in. You can learn more on our how-it-works page. Your maximum loss is limited to your stake — there is no leverage or margin.
When the outcome is determined, winning YES shares pay out $1.00 each in USDC, while losing shares pay $0. Settlement is handled by the UMA optimistic oracle on Polygon — a proposer submits the result, a two-hour dispute window opens, and if uncontested, payouts are distributed automatically. You can withdraw your winnings to any Polygon wallet.
Prediction-market positions can lose 100% of staked capital. Outcomes are uncertain by definition — historical accuracy of crowd-implied probabilities is high in aggregate but not for any single market. PolyGram does not provide investment advice. Trade only with capital you can afford to lose.
Regulatory status varies by jurisdiction. Germany, the United States, and most EU countries treat Polymarket-style event contracts under one of three frameworks: financial derivative, gambling product, or unregulated novel asset. Consult local counsel before trading.
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