Seattle Mariners vs. Kansas City Royals

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Active sub-markets

Market context

Seattle Mariners vs Kansas City Royals is priced on Polymarket at 52% Yes, so the market is only marginally leaning towards a Seattle win. Because the contract is settled in USDC on Polygon through conditional tokens, the main thing to watch is the final official result rather than the scoreline or how the game gets there: a Seattle win pays the Yes side, while any Kansas City victory settles to No, with postponement keeping the market open until completion.

The current price sits in a range that looks consistent with a fairly even matchup rather than a strong directional edge. Recent comparable meetings have been tight: Kansas City beat Seattle 3-2 in extra innings on 2 May, and the Royals’ ability to keep games close has been a recurring theme in the series. For a 52% ask on Seattle, traders are effectively paying for a small favourite margin, not a dominant underlying profile.

The live catalysts are the usual late-notice items: starting pitcher confirmations, batting order changes, and any weather or delay risk that could affect whether the game is played tonight or pushed back inside the settlement window. A recent preview from OddsIndex noted Seattle as a moderate road favourite, while ESPN’s recap of the 2 May game shows how thin the gap can be between these sides when the pitching holds. In practice, the Polymarket contract will track whatever final MLB result is recorded, so lineup and umpire news near first pitch matter more than early market noise.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We track Seattle Mariners vs. Kansas City Royals 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

Where can I trade this market with the lowest fees?

On PolyGram, 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?

PolyGram 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 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.

Do I need to KYC for this market?

Not under $1,500 of lifetime trading volume. Above that threshold, PolyGram 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.