Houston Astros vs. San Francisco Giants

Platform comparison

Market context

The Houston Astros travel to San Francisco on 11 August for a regular-season matchup against the Giants, with first pitch scheduled for 9:45PM ET. The current crowd-implied probability of 22% for an Astros victory suggests the market perceives the Giants as clear favourites in this fixture. Settlement occurs on 19 August, providing a narrow window for monitoring pre-game developments and late-breaking roster changes that could shift algorithmic valuations.

Historical matchup data and recent divisional performance offer useful calibration points for evaluating the 22% baseline. The Astros have maintained a stronger win-loss record than San Francisco across recent seasons, though home-field advantage at Oracle Park carries measurable weight in late-summer baseball. Comparable games between these franchises over the past three seasons show the visiting team winning approximately 35–40% of contests, which would suggest the current probability sits somewhat below historical norms. Traders implementing conditional orders should account for this discrepancy when setting entry thresholds.

Key catalysts to monitor include starting pitcher announcements (typically confirmed 24–48 hours before game time), injury reports affecting either roster, and weather conditions at the San Francisco Bay waterfront, which can influence ball flight and game tempo. Recent roster transactions or mid-season trades affecting either team's bullpen depth warrant programmatic tracking through official MLB sources. Late-arriving line movement from major sportsbooks often precedes significant probability shifts on prediction markets, making cross-platform monitoring essential for identifying mispricing windows before settlement.

Methodology

We track Houston Astros vs. San Francisco Giants 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

Settlement runs on-chain. Polymarket's contract logic separates YES and NO shares as conditional tokens; at resolution the winning share lifts to $1.00 and the losing one to $0. The outcome input comes from the UMA Optimistic Oracle, which secures against bad resolution with a bond + dispute window.

Once finalised, the smart contract pays USDC to the holders' wallets within minutes — no withdrawal fees beyond Polygon network gas. Kalshi settles in USD via CFTC clearance, Betfair in account currency net of commission, Manifold in play-money mana with no cash-out.

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 Fees. 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.

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.

What does Polymarket cost to trade?

Polymarket itself charges 0% — the only cost is the Polygon network fee, typically under $0.01 per transaction. Off-chain venues like Kalshi or Betfair charge 2-7% commission.

Do I need to KYC for this market?

On Polymarket directly, no — it's wallet-based. Intermediary brokers like Kalshi Fees trigger KYC only above $1,500 of lifetime trading volume; under that you trade pseudonymously with a single wallet address.