S&P 500 (SPX) Up or Down on August 3?

Platform comparison

Market context

The S&P 500 has already started the session with a positive tone, after futures rose on easing Middle East tensions and a sharp drop in oil prices, while Friday’s cash close was also firmly higher. That matters for programme-style decision-making because an intraday “Up” market is usually most sensitive to the *previous cash close* reference, not the futures tape itself, so any bot or conditional-order workflow should key off the official close comparison rather than overnight prints.[1][6][15]

For context, the current 100% “Yes” crowd price leaves no room for a directional surprise, which is more typical of a market that has already absorbed the latest catalyst than one that is still pricing a binary event. Recent comparable sessions show why traders should not over-read a single strong close: the index has been swinging around earnings, rates, and geopolitics, with the S&P 500 rebounding after the Fed held rates steady and megacap earnings improved sentiment, yet broader breadth and August seasonality still looked uneven.[3][7][12][13]

The main catalyst stack today is the macro calendar rather than any one headline. Traders watching this programmatically will want to track the final S&P Global US manufacturing PMI release, any follow-through in crude after the Strait of Hormuz talk, and the week’s larger data sequence, especially payrolls, JOLTS, and the ISM manufacturing print, because those can move Treasury yields and equity index futures into the close.[4][6][9][13]

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We track S&P 500 (SPX) Up or Down on August 3? across the five venues with material prediction-market liquidity. The probability shown is the live Polymarket mid; the comparison rows summarise how each venue treats the underlying contract — fees, KYC thresholds, settlement currency, deposit options. The highlighted row marks the cheapest route into Polymarket's order book.

Resolution & payout

Settlement runs on-chain. Polymarket's contract logic separates YES and NO shares as conditional tokens; at resolution the winning share lifts to $1.00 and the losing one to $0. The outcome input comes from the UMA Optimistic Oracle, which secures against bad resolution with a bond + dispute window.

Once finalised, the smart contract pays USDC to the holders' wallets within minutes — no withdrawal fees beyond Polygon network gas. Kalshi settles in USD via CFTC clearance, Betfair in account currency net of commission, Manifold in play-money mana with no cash-out.

FAQ

Where can I trade this market with the lowest fees?

Polymarket is geo-blocked in the US/UK/EU. The easiest 0%-fee broker into the same order book is Kalshi Fees. Kalshi charges up to 7% per trade; Betfair Exchange takes 2-5% commission on net winnings.

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.

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.