Houston Astros vs. Chicago Cubs

Platform comparison

Active sub-markets

Market context

The Houston Astros travel to Chicago to face the Cubs on 23 May at 2:20 PM ET, with the settlement window extending to 30 May to accommodate potential postponements. The 43% crowd-implied probability favours Chicago, reflecting the Cubs' home-field advantage and recent form. Across major platforms, this probability translates differently: Polymarket displays it as a decimal of approximately 1.75 for a Cubs win, whilst Kalshi and Betfair would show comparable odds around 2.33 and 2.30 respectively, depending on their fee structures. Smarkets typically mirrors Betfair's pricing but with lower commission on matched bets, which can shift the effective probability traders face by 1–2 percentage points.

Historical matchups between these franchises show marginal Cubs dominance in recent seasons, though the Astros' 2023–2024 performance has narrowed that gap considerably. The Cubs' win rate at Wrigley Field sits around 52–54% across comparable opponents, suggesting the current 43% for Houston is neither extreme nor dismissive of their capabilities. Traders should note that Polymarket's KYC requirements remain less stringent than Kalshi's, which may affect liquidity and price discovery on this specific market.

Monitoring pitcher assignments is critical; confirmation of starting lineups typically arrives 24–48 hours before game time. Weather conditions at Wrigley—particularly wind direction and temperature—materially affect scoring outcomes. Any roster changes, injuries, or rain forecasts could trigger repricing across all platforms, though Betfair and Smarkets often react faster to breaking news due to their continuous order-book model versus Polymarket's batch-auction structure.

Methodology

We read Houston Astros vs. Chicago Cubs from four platform perspectives: Polymarket (on-chain CLOB), Kalshi (CFTC-regulated exchange), Betfair Exchange (sports book exchange), Smarkets (peer-to-peer betting exchange). Polymarket's live quote comes directly from the Polygon order book; the other three are listed with their platform attributes — fees, KYC, settlement currency, payment options — because a 1:1 contract comparison without API access would be guesswork.

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

Is this market available outside the US?

PolyGram is available in most jurisdictions where Polymarket isn't directly accessible. Polymarket itself is geo-blocked in the US/UK/EU. Always check local regulations.

How does resolution work?

Through the UMA Optimistic Oracle on Polygon: a proposer submits the outcome, a two-hour challenge window opens, and USDC payouts settle automatically once the result is final.

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 it cost to trade on PolyGram?

Zero. PolyGram routes every order to the live Polymarket order book; the only cost is the Polygon network fee, typically under $0.01 per transaction.

How reliable are the quoted odds?

The YES/NO percentages are the live mid-prices of the Polymarket order book. On deep markets they move every few seconds; on thinner ones you'll see short plateaus.