Analytics
“S&P 500 (SPX) Opens Up or Down on March 20?” is a prediction market on Polymarket with two tradeable outcomes, Yes and No. The Yes price is the crowd's implied probability that the question resolves Yes; every trade on the public order book moves it.
The venue reports this market as closed. Its scheduled close is Mar 20, 2026. No resolved outcome is inferred from a closed or suspended state.
Vultax observes this market from Polymarket's public order book and data API and keeps its own record: 27 loaded holder wallets, the largest ten holding 96.7% of the loaded shares; 500 recent public fills from 161 wallets. Each figure carries its observation time; nothing here is a return forecast.
Public Polymarket market/event context is available; Vultax source-pack coverage is tracked separately.
This resolved market has no live orderbook depth; the public close quote is shown for context.
Nine stops, one per figure on this page. Each stop says what the number is, why it matters, and what it reads right now for this market.
Each outcome trades as a share that pays $1 if it wins and nothing if it loses. Prices are quoted in cents, and Yes plus No add up to about one dollar.
| Trader | Outcome | Shares |
|---|---|---|
| Actual-Replication | Up | 3K |
This market will resolve to "Up" if the official S&P 500 Index open price for S&P 500 (SPX) on March 20 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 March 20 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. If the two prices are exactly equal, this market will resolve 50-50. Note that all figures will be rounded to the nearest cent using standard rounding. If SPX does not trade at all during the regular session, the market will resolve 50-50. If either of the relevant days are shortened (for example, due to a market holiday schedule), the official open/close price published by S&P 500 Index for that shortened session will still be used for resolution. If the previous trading day has no official closing price (for example, due to a trading halt into the market 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 the Wall Street Journal, specifically the Open/Close values published by the WSJ under "Historical Prices". US: https://www.wsj.com/market-data/stocks EMEA: https://www.wsj.com/market-data/stocks/emea ASIA: https://www.wsj.com/market-data/stocks/asia
Resolution source: https://www.wsj.com/market-data/stocks
Official listing: polymarket.com/event/spx-opens-up-or-down-on-march-20-2026
The Yes price read as a chance. A share at 21.5¢ means the crowd gives Yes about a 21.5% chance right now. It moves with every trade, so it is a live forecast, not a verdict.
Dollar value of shares that changed hands in the last 24 hours. High volume means the price is being tested by real money; low volume means a few trades can move it.
Dollars resting in the order book, waiting to be traded against. Deep liquidity lets a large order fill near the quoted price; thin liquidity means the price jumps when someone trades size.
The gap between the best bid and the best ask. A tight spread makes entry and exit cheap; a wide spread is a cost paid on every round trip.
The wallets holding the most shares on each side, and how much of the loaded sample the largest ten control. Concentration shows whether a market is a crowd or a handful of large positions.
The public fills, newest first: which wallet bought or sold which outcome, at what price, and when. It is the market's own diary, and every wallet on it links to a trader profile.
Hourly closes of the Yes price. The range shows how sure or split the crowd has been; the move shows which way it has been changing its mind.
Trading stops at the close time. The outcome is then settled by the resolution source named in the rules. A closed market is not resolved until the venue reports it, so the two states are shown separately.
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