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

Platform comparison

Market context

Polymarket’s contract is trading near **48% YES**, which implies the market is close to a coin flip on whether the S&P 500 closes above Tuesday’s level, rather than pricing a clear directional edge. On the mechanics side, that payout is determined by a USDC-settled conditional token on Polygon, so the only thing that matters is the official SPX close relative to the prior trading day’s close, not intraday swings or where the cash index trades after the close.

That near-even price fits the recent tape. The S&P 500 finished Tuesday at **7,509.20**, after a **0.9%** gain, with technology and semiconductors doing much of the lifting even as tariff headlines and Middle East tensions stayed in the background.[1] In practical terms, a trader reading this market is looking at whether today can extend that momentum or whether profit-taking and headline risk flatten the index by the settlement close.

For the day’s catalysts, watch the usual close-to-close drivers: any late-session reaction to trade or tariff comments, moves in megacap tech, and whether energy strength persists. The market has already shown it can shrug off geopolitical noise when large-cap growth is firm, but a softer risk tone would matter because this contract resolves strictly on the official close. The S&P 500 opened today at **7,489.95**, which leaves relatively little room before the market needs only modest afternoon strength to finish up on the day.[2][1]

Sources: 1 · 2 · 3

Methodology

This page reviews S&P 500 (SPX) Up or Down on July 22? across five venues. The live probability is the Polymarket mid-price, sourced directly from the on-chain Polygon order book; the comparison columns benchmark each venue on fee structure, KYC, settlement currency and payment rails. Every CTA routes to PolyGram, which mirrors the Polymarket order book at 0% fees.

Resolution & payout

At resolution the UMA oracle takes over: a proposer posts the outcome with a bond, any token holder can dispute within two hours. Without dispute the result is accepted and the smart contract distributes USDC instantly.

On Kalshi (CFTC-regulated) resolution runs through their in-house clearing engine in USD. Betfair Exchange settles after match end in the account's local currency. Manifold pays no cash — only its in-platform "mana" currency.

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.