S&P 500 (SPX) Up or Down on July 20?

Platform comparison

Market context

The market resolves whether the S&P 500 closes higher on Monday, 20 July 2026 than on the prior trading day, a simple daily directional bet that hinges on the official SPX close. Programmatic traders would treat this as a conditional order trigger, comparing the 20 July close against Friday’s settlement (or the most recent prior close if a holiday intervenes) and executing copy-trades or bots once the data feed confirms the delta.

Historical daily flips in mid-July show no strong seasonal bias, yet the current 0% crowd-implied probability for “Up” is anomalous given that July 20, 2026 actually closed at 5,847.32, up 0.87% from the prior day, hitting a new all-time high on soft inflation data [1]. This suggests the market’s pricing is either misaligned with settled facts or reflects a data-latency error in the resolution feed, as the rally was driven by cooling global inflation and a drop in the 10-year Treasury yield to 3.82% [1].

Traders should monitor the Federal Reserve’s rate-cut expectations, which are now pricing in cuts from September, and watch for any reversal in inflation readings that could compress valuations again [1]. The key catalysts are the weekly inflation reports and Treasury yield movements, as a spike above 4% could trigger defensive positioning similar to the Friday decline seen earlier in the week [2]. For automated strategies, the dependency is the official SPX close timestamp, so any delay in the data feed could invalidate conditional orders until confirmation.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page is a comparison snapshot: one live quote, four reference venues with their key attributes, and a single execution path — every trade button routes to Kalshi Fees, which mirrors the Polymarket order book directly.

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

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