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

Platform comparison

Market context

The S&P 500 has already printed an open above the prior close, so the contract is effectively a question of whether the August 3 opening print finishes **Up** or **Down** versus the last trading day’s close. The market has also shown a strong bullish gap in pre-market pricing, with one live briefing putting SPX about 0.5% higher before the bell and another open print at 7,366.51, while Friday’s close was reported at 7,489.72, which is the reference point for this event.[3][10][7]

That backdrop makes the current **100% YES** crowd price look much more extreme than the broader cross-platform signal. Prediction-market listings shown in search results are far lower, including a Bitget contract at 22%, while futures commentary and market coverage point to a positive but not unanimous risk-on tone rather than certainty.[18][5][13] In comparable cases, the first print is usually driven by overnight futures, but the open can still be pulled around by late macro headlines and dealer hedging, especially when the session starts near a technical range or options “call wall”.[10][17]

Traders should watch the morning US data calendar, particularly the ISM manufacturing release and construction spending, both cited as key Monday catalysts, because a surprise there can quickly change Treasury yields, the dollar and index futures before the open.[17][19] Oil is another live variable: several reports noted weaker crude helping equities, and that relationship matters because softer energy prices can support growth multiples while firmer yields or geopolitical headlines can reverse an overnight gap.[2][20][14]

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We track S&P 500 (SPX) Opens 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 Best Prediction Markets. 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.

How does resolution work?

Through the UMA Optimistic Oracle on Polygon: a proposer submits the outcome, a two-hour challenge window opens, and USDC payouts settle automatically once the result is final.

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.