Seattle Mariners vs. Cleveland Guardians

Platform comparison

Active sub-markets

Market context

The underlying event is the Major League Baseball match between the Seattle Mariners and Cleveland Guardians, scheduled for 7:10pm ET on 26 June at Progressive Field in Cleveland. The Mariners, currently 41-41 and leading the AL West, face the Guardians, who sit 42-39 and second in the AL Central. The crowd-implied probability of 100% YES for the Mariners to win is an extreme outlier in sports prediction markets, where outcomes are rarely guaranteed.

Historically, such absolute certainty in baseball markets has only appeared when a game was postponed or when a team faced a non-competitive opponent, neither of which applies here. Comparable cases from the 2024 and 2025 seasons show that even favoured teams with 60%+ win probabilities have lost roughly 40% of their games, making a 100% market price highly suspect unless a settlement error has occurred.

Traders should monitor immediate catalysts including Luis Castillo’s starting status, as his career .217 average against right-handed batters could shift momentum, and any official MLB announcements regarding game postponement. Recent campaign-finance disclosures from team ownership groups have not yet influenced roster decisions, but the market appears to lean on the assumption that the Mariners’ pitching will dominate. For real-time updates on starting lineups and weather conditions, consult ESPN’s live game coverage [1] or the official MLB game preview [8]. No moralising on trade viability is offered; the facts remain that the probability is statistically anomalous for a live contest.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page tracks Seattle Mariners vs. Cleveland Guardians across four political prediction venues. Live odds come from the Polymarket order book (the deepest political prediction-market book). Kalshi is the CFTC-regulated US alternative, Betfair the established UK sports-exchange with politics markets, Manifold the open play-money variant. Trump Prediction routes every trade through to Polymarket — at 0% fees.

Resolution & payout

Political markets typically settle on official candidate or agency confirmation. Polymarket uses UMA Optimistic Oracle: a proposer posts the outcome with a bond, the two-hour window opens, then the smart contract pays USDC.

Kalshi settles USD via CFTC clearinghouse, with clearly defined resolution sources (e.g. AP race calls for elections). Betfair settles after the official outcome is registered with the league or agency. Manifold is play-money.

FAQ

Where can I trade this market with the lowest fees?

On Trump Prediction, which mirrors the Polymarket order book at 0% fees. Kalshi charges up to 7% per trade; Betfair Exchange takes 2-5% commission on net winnings.

Is this market available outside the US?

Trump Prediction 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.

Do I need to KYC for this market?

Not under $1,500 of lifetime trading volume. Above that threshold, Trump Prediction triggers a quick verification flow that finishes in minutes.