Bitcoin Up or Down - August 17, 12:00AM-4:00AM ET

Platform comparison

Market context

Bitcoin's four-hour price movement between 12:00 and 4:00 AM ET on 17 August will be measured using Chainlink's BTC/USD time-weighted average price feed, which aggregates data across major exchanges at 60-second intervals. The market resolves "Up" if the TWAP at the window's close meets or exceeds the opening level; any decline triggers "Down". For traders building conditional logic around this window, the Chainlink feed offers programmatic certainty—no manual price-checking required—making it suitable for automated strategies that need deterministic settlement tied to institutional-grade price data rather than spot quotes from individual exchanges.

The 100% probability currently reflected suggests either extreme confidence in overnight Bitcoin stability or limited liquidity in this specific four-hour window. Historical precedent shows overnight Asian-to-European trading sessions typically exhibit lower volatility than US market hours, though this varies sharply depending on macroeconomic releases or geopolitical developments. Bitcoin's overnight behaviour has historically favoured modest consolidation rather than directional moves, particularly when no major announcements are scheduled.

Traders should monitor whether any Federal Reserve communications, inflation data, or cryptocurrency-specific regulatory announcements fall within or immediately precede this window. Recent volatility has been driven by broader equities sentiment and USD strength rather than Bitcoin-specific catalysts. Integrating this market into a bot-based strategy requires confirming Chainlink's feed uptime and understanding any potential delays in TWAP calculation; querying the data stream directly before the settlement deadline ensures no discrepancies between expected and actual resolution prices.

Methodology

We track Bitcoin Up or Down - August 17, 12:00AM-4:00AM ET 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

At resolution the UMA oracle takes over: a proposer posts the outcome with a bond, any token holder can dispute within two hours. Without dispute the result is accepted and the smart contract distributes USDC instantly.

On Kalshi (CFTC-regulated) resolution runs through their in-house clearing engine in USD. Betfair Exchange settles after match end in the account's local currency. Manifold pays no cash — only its in-platform "mana" currency.

UK Frequently Asked Questions

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.

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.

Is Polymarket legal in the UK?

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%.