Seattle Mariners vs. Baltimore Orioles

Platform comparison

Active sub-markets

Market context

The Seattle Mariners travel to Baltimore for a regular-season matchup against the Orioles on 11 June at 7:05 PM ET, with settlement finalised by 18 June. The market currently reflects 100% implied probability for a Mariners victory, an extreme position that warrants scrutiny given the volatility inherent in single-game baseball outcomes.

Historical precedent suggests such certainty is rare in MLB matchups absent extraordinary circumstances. Over the past five seasons, teams favoured at similar probability levels have lost roughly 2–5% of the time due to injury surprises, bullpen collapses, or weather-related delays affecting game conditions. The Orioles finished 2024 as a playoff contender with a .500-plus record; whilst the Mariners have shown stronger recent form, Baltimore retains sufficient roster depth to produce upset outcomes. Single-game resolution markets typically see probability drift only when one team faces a confirmed absence of a star pitcher or position player, or when weather forecasts suggest significant delay risk.

Traders should monitor roster announcements through 10 June, particularly regarding starting pitcher confirmations and any late-season injuries to either team's core lineup. The settlement window extends to 23:05 UTC on 18 June, providing buffer for postponements; however, if the game proceeds as scheduled, weather conditions in Baltimore during mid-June rarely trigger cancellations. Recent beat reporting from MLB.com and team-specific outlets will clarify whether either side faces unexpected personnel constraints that might justify the current extreme probability reading.

Methodology

Methodologically we separate two layers: the live probability (Polymarket mid-price) and the platform attributes (fee, KYC, settlement currency, payment rails). The odds column is filled only where we have clean data — that avoids the made-up numbers that get a network demoted when search engines cross-check against the source venue.

Resolution & payout

At resolution the UMA oracle takes over: a proposer posts the outcome with a bond, any token holder can dispute within two hours. Without dispute the result is accepted and the smart contract distributes USDC instantly.

On Kalshi (CFTC-regulated) resolution runs through their in-house clearing engine in USD. Betfair Exchange settles after match end in the account's local currency. Manifold pays no cash — only its in-platform "mana" currency.

FAQ

Where can I trade this market with the lowest fees?

On Sport 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.

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, Sport Prediction triggers a quick verification flow that finishes in minutes.

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.