Seattle Mariners vs. Baltimore Orioles

Platform comparison

Active sub-markets

Market context

The Seattle Mariners travel to Baltimore on 9 June 2025 for a regular-season Major League Baseball fixture against the Orioles, with first pitch at 6:35 PM Eastern Time. The market resolves to the winner of that single game, with a settlement window extending to 16 June 2025 to accommodate any postponements. Official MLB final statistics serve as the authoritative resolution source; cancellations without rescheduling or tied results trigger a 50-50 split.

The 100% crowd-implied probability reflects either extreme confidence in one outcome or illiquidity in the order book. Comparable MLB game markets typically show material two-way probability unless one team carries a decisive advantage in starting pitcher quality, injury status, or recent form. The Mariners and Orioles have traded competitive seasons in recent years, with neither franchise commanding the kind of structural dominance that would justify near-certain pricing in a single-game contest. Traders should verify whether this probability reflects genuine conviction or sparse liquidity before committing capital.

From a regulatory standpoint, this market's accessibility depends on trader jurisdiction. Under German GlüStV rules, prediction markets on sports outcomes face stricter licensing requirements than financial derivatives, though cross-border participation remains common. US CFTC oversight applies to binary sports contracts offered to US persons, though enforcement varies by platform registration. The "no-KYC up to $1,500" threshold often cited in crypto prediction markets does not apply uniformly here; UK-domiciled platforms typically require identity verification regardless of stake size for sports betting compliance. Traders should confirm their platform's specific KYC thresholds and jurisdictional restrictions before placing orders.

Methodology

We track Seattle Mariners vs. Baltimore Orioles on the five venues with material liquidity for prediction markets. Live odds come from the Polymarket Polygon order book — the only source that ships real-time data under an open licence. For Kalshi, Betfair and Manifold we list platform attributes (fee, KYC, settlement, payment) instead of fabricated odds, because their APIs use non-comparable contract definitions.

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

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 Polymarket Tax UK?

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

How fast are USDC deposits?

Polygon credits deposits after 12 confirmations — usually under 30 seconds. Withdrawals follow the same path and land back in your wallet within 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.