SPY (SPY) Up or Down on July 22?

Platform comparison

Market context

SPY is a liquid proxy for the S&P 500, so this market is really a bet on whether the ETF closes above its most recent prior close by the session close on 22 July, rather than on intraday volatility. The current crowd-implied 72% YES is consistent with a mild upward bias, but it still leaves meaningful scope for a one-day reversal, especially because the reference is the close versus the previous trading day, not the open or an intraday peak. Recent quotes put SPY in the high-740s, with Investing.com showing 749.79 against a previous close of 748.28 and Macrotrends showing a late-June closing level of 732.97, underscoring that the instrument has already moved materially within the current quarter.[3][5]

For comparison, Polymarket-style markets usually display implied probability directly, while Kalshi and Betfair-style books are easier to read through price and decimal odds, so the same view can look different once fees are included. Smarkets also charges commission rather than embedding all costs in the displayed probability, and KYC access can vary by platform and jurisdiction, which affects who can participate and at what effective price. For this specific event, traders will mainly watch the US market close, any late-session macro releases, and whether SPY tracks a broader risk-on move or fades into the bell; the settlement is determined solely by the official close on the expiry date versus the prior trading close, so the last hour matters more than the day’s earlier range.[1][2][3]

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page compares SPY (SPY) Up or Down on July 22? specifically across Polymarket, Kalshi, Betfair Exchange and Smarkets. The live probability is the Polymarket mid; the comparison columns summarise each venue's fee structure, KYC, settlement currency and payment rails. Every CTA routes to Kalshi Alternative UK, which mirrors the Polymarket order book at 0% fees.

Resolution & payout

Polymarket settles via UMA Optimistic Oracle on Polygon. A proposer posts the outcome with a bond, the two-hour window runs, then the smart contract pays USDC.

Kalshi settles USD through the CFTC-regulated clearinghouse — the cleanest variant, with heavier KYC. Betfair Exchange settles in account currency (GBP/EUR), net of 2-5% commission. Smarkets follows the same model as Betfair with a lower default 2% commission.

FAQ

What does Polymarket cost vs Kalshi?

Polymarket: 0% fees, only Polygon network costs (~$0.01/trade). Kalshi: up to 7% per trade plus spread. For high-frequency traders, Polymarket is dramatically cheaper.

Which platform has the deepest liquidity?

Polymarket — by a wide margin. Top markets reach $50-500M volume, Kalshi ~$200M cumulative, Betfair similar. Deeper liquidity means your trade moves the quote less.

Which platform is accessible globally?

Polymarket is geo-blocked in the US/UK/EU. Kalshi is US-only. Betfair and Smarkets are UK-restricted. Kalshi Alternative UK has a different geo footprint and routes to Polymarket's order book at 0% fees.

Are all these platforms regulated?

No. Kalshi is CFTC-regulated (US). Betfair and Smarkets are UK Gambling Commission licensed. Polymarket operates without explicit regulation — a different risk profile than a regulated sportsbook.

Which platform supports Klarna/SOFORT?

Directly: none. Polymarket accepts only USDC on Polygon. Kalshi Alternative UK offers a fiat on-ramp via Klarna or SOFORT (DE/AT/CH) and converts internally to USDC for the Polymarket order book. T+1 processing.