Miami Marlins vs. Houston Astros

Platform comparison

Market context

The Houston Astros defeated the Miami Marlins 8–5 in their MLB game on Monday, 20 July 2026, at Daikin Park in Houston, with Jeremy Peña hitting a grand slam and Yordan Alvarez scoring two home runs [1][4]. This result means the prediction market titled “Miami Marlins vs. Houston Astros” has already settled: the contract resolves to “Houston Astros,” and the YES probability for a Marlins win is now 0% as the game is complete [1].

On Polymarket, this contract trades in USDC on Polygon using conditional tokens, and its price collapsed to zero once ESPN and CBS confirmed the final score [1][4]. Historically, similar MLB markets with 0% crowd-implied probability after game completion have never reopened, as the governing body’s official statistics lock the outcome immediately [1]. Traders who held YES positions before the result faced total loss, while NO holders captured full payout, reflecting the on-chain settlement mechanics that enforce finality once the event concludes.

With the game already played, there are no further catalysts to watch—no pitching changes, schedule shifts, or postponement risks remain [3][5]. The settlement window ending 2026-07-28 is irrelevant now, as resolution occurred at game end. Any lingering open orders would be auto-cancelled by the platform’s oracle feed upon confirmation of the final score from MLB’s official stats [1].

Sources: 1 · 2 · 3 · 4 · 5

Methodology

Methodologically we separate two layers: the live probability (Polymarket mid-price) and the platform attributes (fee, KYC, settlement currency, payment rails). That keeps the comparison honest — a single canonical probability across the row, with the venue-by-venue trade-offs spelt out in the columns next to it.

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.

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 UK. 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.

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.

Do I need to KYC for this market?

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

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.