The Prediction Markets

S&P 500 (SPX) Up or Down on October 22?

Full timeKickoff Waiting for the venues to settle
Traded
$24K
Venues
Polymarket
Prices updated
just now
Share

What the markets expect

Yes 0.1%

Only Polymarket lists this market, so there is no second price to compare.

Yes 0.1%No 100%

Odds by venue

Fair chance strips out each venue’s built-in margin (its prices add up to more than 100%), then blends the venues by how much has traded there, so the outcomes add up to 100%. Best Yes price is the cheapest ask across venues, and the payout is what a winning $100 stake returns before fees. Open a row for each venue’s contract name, bid and ask, and how closely their rules match.

Prices come from our regular polls of each venue. Ages are as of when this page was built.

  • Polymarket
Yes
0.1%
Polymarket 0.1%polled, 38s ago
Polymarket
Contract
Yes
Last price
0.1%
As of
Polled just now
Buy Yes
—
Sell Yes
—
Volume
$24K
Trade this on Polymarket

Who resolves this market

Polymarket
Polymarket resolves via:
UMA optimistic oracle, source: wsj.com

How the odds have moved

The leading outcome on both venues, with the consensus between them. Hover for exact values.

  • Yes

Order books

Each venue’s resting orders for the Yes contract, side by side. Top of book streams live; depth refreshes every 15 seconds.

Polymarket

Open on Polymarket ↗

Top of book

Connecting
Best bid
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Spread
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Best ask
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Waiting for the first live quote…

Depth · top 8 levels

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Recent trades

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What your stake buys

Enter a stake to see where it buys the most after fees, using each venue’s live order book.

$
Buy

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Cover Yes and No across venues

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Buys at the asks resting now (taker orders), cheapest after fees first, from order-book snapshots up to 15 seconds old. Fees: Kalshi 0.07 × price × (1 − price) per share, rounded up to the cent; Polymarket 0.05 × price × (1 − price) per share (other / general rate). Fee calculator. Estimates only, not advice.

About this market

Live prediction market odds for "S&P 500 (SPX) Up or Down on October 22?". Yes leads at 0.1%. $24K has traded across 1 outcome on Polymarket. The market is expected to resolve by Oct 22, 2026.

This market will resolve to "Up" if the official S&P 500 Index closing price for S&P 500 (SPX) on Thursday, October 22, 2026 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 closing price for S&P 500 (SPX) on Thursday, October 22, 2026 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 specified closing 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 closing price published by S&P 500 Index for that shortened session will still be used for resolution. If either of the relevant days have 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 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

Questions

What does the consensus price mean?

It is the price of a Yes contract that pays $1 if the outcome happens. A 14¢ price means traders put the chance near 14%. Where two venues list the same outcome, we blend their last prices, weighting the venue with more trading volume more heavily (neither counts for less than a quarter). When only one outcome can win, each venue’s prices add up to a little over 100% (its margin); the fair chance removes that margin so the outcomes add up to exactly 100%.

How is the payout worked out?

A Yes contract pays $1 if it wins, so at the best ask a $100 stake buys 100 ÷ ask contracts. At 18¢ that is about 555 contracts, paying $556 (5.56x) if Yes happens. Venue fees and price slippage on larger orders are not included.

Why do the venues show different prices?

Each venue has its own traders, fees and order book. Contracts can also settle on slightly different terms, which is why each row lists how closely the rules match.

Is a price gap an arbitrage?

Only when you can buy Yes on one venue below what someone pays for Yes on the other, after fees, and both contracts settle the same way. We show the executable bid and ask so you can check.

How fresh are these prices?

Venue prices refresh every few minutes, and the order book and live quotes stream continuously. Each venue’s card shows when we last observed it.

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