Houston Astros vs. San Francisco Giants

Platform comparison

Market context

The Houston Astros face the San Francisco Giants on 11 August at 21:45 ET in a regular-season MLB matchup. The 0% implied probability displayed here reflects either extreme illiquidity on this particular market or a data-lag issue across platforms—a common friction point when comparing Polymarket's order-book depth against Kalshi's more structured contract design. Kalshi's binary settlement (Astros win or Giants win, with 50-50 resolution only if cancelled) removes ambiguity around extra innings or postponements, whereas some books require explicit tie-handling rules that traders must parse before committing capital.

As of early August 2024, the Astros maintain a stronger win-loss record and playoff positioning than the Giants, who have struggled with inconsistent pitching depth. Historical matchups between these clubs show the Astros' recent dominance, though August baseball introduces fatigue variables and roster adjustments that shift single-game probabilities sharply. Traders should monitor injury reports for both teams' starting pitchers—a late scratch can swing fair odds by 5–8 percentage points—and track any weather delays that might affect the evening start time in Houston's humid climate.

The settlement window extends to 19 August 2026, an unusually distant deadline that suggests this market may be a historical record or test listing rather than live trading. Fee structures vary meaningfully across platforms: Kalshi charges a flat 2% on net winnings, whilst Polymarket's variable maker-taker model and Betfair's commission-on-profit approach create different effective costs for position sizing. Verify the market's current liquidity and settlement terms on your chosen platform before entry.

Methodology

This page compares Houston Astros vs. San Francisco Giants 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, 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.

Is Betfair a Polymarket alternative?

Only partially. Betfair Exchange is UK-focused with a sports-betting emphasis; they have politics markets but with thinner liquidity than Polymarket. Settlement in GBP/EUR, 2-5% commission on winnings.

What about Smarkets as an alternative?

Smarkets is a UK betting exchange with a lower default commission (2%) than Betfair. Liquidity on political markets is below Polymarket, comparable to Kalshi. Geo-blocked in many jurisdictions.

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 has a different geo footprint and routes to Polymarket's order book at 0% fees.