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

Platform comparison

Market context

Polymarket is pricing this S&P 500 close-to-close contract at **75% YES** right now, with settlement tied to whether the official SPX close on 22 July is above the prior trading day’s close. On the platform, that view is expressed in **USDC** on **Polygon**, using conditional tokens that pay out according to the index settlement rule rather than the intraday move.

That 75% implies traders are leaning towards another higher close after Tuesday’s advance. Zacks reported that Wall Street ended Tuesday higher, with the S&P 500 up **65.92 points, or 0.9%**, to **7,509.20**, helped by tech and energy shares even as tariff headlines and Middle East tensions stayed in view. The backdrop matters because same-day “up or down” markets are usually a read on whether momentum can survive the final auction, not just on the day’s early trade.

For a Polymarket user, the main watchpoints are the late-session drivers that can flip a marginally green market: major earnings hits, macro releases, Federal Reserve commentary, and any tariff or geopolitical headlines that affect index futures into the close. The opening level was reported at **7,489.95** by Investing.com, while StatMuse showed the latest price at **7,521.56**, indicating the index had already held above Tuesday’s close intraday, but the contract still depends on the official 20:00 UTC settlement print.

Sources: 1 · 2 · 3

Methodology

Methodologically we separate two layers: the live probability (Polymarket mid-price) and the platform attributes (fee, KYC, settlement currency, payment rails). That keeps the comparison honest — a single canonical probability across the row, with the venue-by-venue trade-offs spelt out in the columns next to it.

Resolution & payout

Polymarket-based markets settle through the UMA Optimistic Oracle on Polygon. A proposer submits the outcome, a two-hour challenge window opens, and unchallenged proposals finalise the resolution. Payouts settle automatically in USDC the moment the result is final — no bookmaker, no delay.

Kalshi-based markets settle in USD via the CFTC-regulated clearinghouse. Betfair Exchange settles in GBP/EUR net of commission. Manifold is play-money and does not pay out real funds.

FAQ

Is this market available outside the US?

Polymarket itself is geo-blocked in the US/UK/EU. Always check the legal status of prediction markets in your jurisdiction before trading.

What's the difference between YES and NO shares?

A YES share pays $1.00 if the event happens, $0 otherwise. A NO share pays $1.00 if the event doesn't happen. The market price between 0¢ and 100¢ is the implied probability.

What does Polymarket cost to trade?

Polymarket itself charges 0% — the only cost is the Polygon network fee, typically under $0.01 per transaction. Off-chain venues like Kalshi or Betfair charge 2-7% commission.

How fast are USDC deposits?

Polygon credits deposits after 12 confirmations — usually under 30 seconds. Withdrawals follow the same path and land back in your wallet within minutes.

How reliable are the quoted odds?

The YES/NO percentages are the live mid-prices of the Polymarket order book. On deep markets they move every few seconds; on thinner ones you'll see short plateaus.