S&P 500 (SPX) Up or Down on August 6?

Platform comparison

Market context

The S&P 500 finished **lower on 6 August 2026**, so this market’s implied probability of **0% YES** is aligned with the realised outcome rather than a live toss-up. On the available closes, the index slipped about 0.2% to **7,709.96** on Thursday, having been just below a record set earlier in the week, which means the “Down” side was the favourite into settlement and the “Up” side had no evident value after the fact.[3]

For framing, it helps to separate the day’s move from the broader tape: the index had been sitting near record territory and was still up **2.9% for the week** and **12.6% for the year**, which is the sort of elevated backdrop that often makes single-session direction more sensitive to late-session profit-taking than to the longer trend.[3] By contrast, some reports described the session as a fresh record close or a strong tech-led advance, but those accounts conflict with the official close data showing a decline, so the closing print is the cleaner guide for this market.[4][6]

The main catalysts to watch for any same-day SPX handicap are the US economic calendar, Treasury yield moves, and mega-cap earnings, because those can quickly change whether dip-buyers or sellers control the close. A contemporaneous market wrap said the next key test was the **jobs report** and Federal Reserve rate-cut expectations, with traders also reacting to earnings and tech leadership; in practice, that means the consensus leans heavily on macro releases and Fed signalling, while contrarian angles usually come from sharp intraday reversals after strong opens.[4][12]

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We track S&P 500 (SPX) Up or Down on August 6? 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

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.

UK Frequently Asked Questions

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 Who Will Win. 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.

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Polymarket is accessible to UK traders but is not UKGC-licensed. It operates under US CFTC jurisdiction. UK residents face no domestic legal prohibition on using it, but UKGC consumer protections do not apply. For UKGC-regulated alternatives, Betfair Exchange and Smarkets offer similar prediction-style markets.

Do I pay tax on prediction market profits in the UK?

UKGC-licensed platform profits (Betfair, Smarkets) are typically tax-free gambling winnings for UK individuals. Polymarket profits involve USDC crypto transactions, which HMRC treats as Capital Gains Tax events. Keep full transaction records and report via Self Assessment if gains exceed £3,000 per tax year.

How do I deposit on Polymarket from the UK?

UK traders typically fund Polymarket via Coinbase UK, Kraken or Revolut — buying USDC with GBP and transferring to a Polygon-compatible wallet (MetaMask, Coinbase Wallet). Polymarket's onboarding walks you through the bridging process. Typical GBP-to-USDC conversion costs 0.5–1%.