Pronóstico: S&P 500 (SPX) Up or Down on July 9?

Platform comparison

Market context

The S&P 500 closing price on Thursday, 9 July 2026 is currently priced at a 100% probability of being higher than the prior trading day’s close, implying a near-certain daily gain. On Polymarket, this contract trades with full USDC backing on the Polygon chain, where conditional tokens lock in the outcome before settlement. The market resolves strictly on the official SPX close, not futures or intraday moves, making it a pure on-chain bet on the index’s daily direction.

Historically, such 100% implied probabilities in daily SPX markets are rare and often precede volatility spikes or data surprises. In comparable cases, like the 2023 Q2 earnings season, markets with near-total certainty saw reversals when unexpected macro data emerged. The 52-week range for SPX sits between 6,201.59 and 7,620.90, with the index currently near 7,480.70, suggesting limited upside cushion before resistance[2]. Traders should note that a 100% probability rarely holds through major announcements.

Key catalysts include the July 9 FOMC meeting minutes release and the upcoming Q2 GDP preliminary figure, both scheduled for early July. A recent MarketWatch analysis notes that SPX sensitivity to rate expectations has increased, with a 5-day change of -1.53% and a 1-month decline of -6.27%[4]. Traders must monitor the USDC liquidity depth on Polygon and any conditional token imbalances, as these reflect on-chain sentiment shifts before the official close.

Sources: 1 · 2 · 3 · 4 · 5

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

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

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'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 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.