S&P 500 (SPY) closes above … on July 13?

Platform comparison

Market context

The S&P 500 tracking fund SPY will settle based on its closing price on 13 July 2026. The current 0% crowd-implied probability suggests the market is pricing in either an extremely low likelihood of the specified threshold being breached, or insufficient liquidity and clarity around the exact strike price in question. This disconnect between sportsbook pricing on equity indices and prediction-market odds often reflects different trader bases: traditional options markets price tail-risk premiums that prediction markets sometimes underweight, whilst retail prediction-market participants may anchor to recent volatility regimes rather than forward-looking distributions.

Historical precedent shows that single-day S&P 500 moves exceeding 2–3% occur roughly 5–10 times annually under normal market conditions, though clustering around earnings seasons, Federal Reserve decisions, and macroeconomic data releases skews the distribution. July typically sees lower trading volumes as summer holidays approach, which can amplify intraday swings but also reduce institutional participation. The 13th falls mid-month, outside major FOMC windows and earnings blackout periods for most large-cap constituents.

Traders monitoring this contract should track any scheduled economic data releases in the week prior—particularly inflation or employment figures—and watch for geopolitical or corporate-action announcements that might drive broad index repricing. Implied volatility levels on SPY options chains will signal whether options markets are pricing elevated tail risk for that specific date. Divergence between Kalshi and Polymarket odds on this contract would reflect differences in their user bases' risk appetites and information sets rather than fundamental disagreement on market mechanics.

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

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 vs Polymarket. Kalshi charges up to 7% per trade; Betfair Exchange takes 2-5% commission on net winnings.

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.

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.