Boston Red Sox vs. Seattle Mariners

Platform comparison

Active sub-markets

Market context

Polymarket is pricing this **Boston Red Sox vs Seattle Mariners** contract at **100% YES**, which means the market is effectively treating a Red Sox win as fully reflected in the current USDC price on Polygon. For a user holding the on-chain conditional token, the practical question is not the abstract matchup but whether the official final result for the June 20 game matches the Red Sox side before the settlement window closes on 2026-06-28T02:10:00Z.

The clearest comparable read-through is the same two-club pairing one night earlier, when Seattle announced a schedule change and the first game of the set moved to Friday, June 19, with the Red Sox winning 6-2 in the finished game.[3][1] FOX Sports’ live boxscore for the June 20 meeting also shows the game listing and betting context, while ESPN has the matchup on its live game page, indicating this was the scheduled contest Polymarket users are tracking for final stats-based settlement.[2][4] In markets like this, a 100% price usually means the outcome has been effectively decided by the event state rather than by any remaining uncertainty in the contract itself.

What a trader still has to watch is whether the game was completed, postponed, or voided, because the market rules keep it open if postponed and split 50-50 only if cancelled or tied. The key dependency is the official MLB final statistics, not media recap or scoreboard snapshots, and the schedule change already shows that this series has had moving parts.[3] If there is any delay, make-up scheduling, or later correction to the official result, that would matter more than pre-game sentiment for Polymarket’s conditional token settlement.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We track Boston Red Sox vs. Seattle Mariners 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

Is this market available outside the US?

Kalshi UK 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 Kalshi UK?

Zero. Kalshi 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.