Seattle Mariners vs. Kansas City Royals

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Active sub-markets

Market context

The Seattle Mariners and Kansas City Royals are due to meet in an MLB game, and this market settles on which club wins outright. In prediction markets, a YES share means the named outcome happens and a NO share means it does not; at a 52% crowd-implied price, the market is signalling only a slight lean rather than a strong view. That is a useful way to read a close baseball matchup, where one swing, bullpen change or late defensive play can flip the result.

Recent comparable meetings suggest there is not much separation between these teams. Kansas City edged Seattle 3-2 on 2 May, with Maikel Garcia driving in the winning run in extra innings after a strong outing from Mariners starter Emerson Hancock. Over the longer head-to-head sample, StatMuse shows the clubs have played relatively tight games, with a combined run environment that has not produced many one-sided results. That history fits a market price close to even money, because outcomes have often been decided by narrow margins rather than sustained dominance.

For traders, the main catalysts are the confirmed starters, line-up cards and late bullpen availability. A left-right pitching matchup matters because both teams have shown stronger and weaker splits depending on the opposing starter, and any late scratch can move the fair price quickly. The other key dependency is schedule context: extra-inning games or recent bullpen use can shape late scoring more than the pre-game headline line. MLB’s official game preview and final statistics are the primary reference points if the contest is completed as scheduled.

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Methodology

This page reviews Seattle Mariners vs. Kansas City Royals across five venues. We show live odds for Polymarket-based markets (sourced from the Polygon order book); for other venues we list platform attributes, since the comparable contracts are not exposed via a public API on every venue. Every CTA points at PolyGram — the application we operate, where you trade directly against the Polymarket order book at 0% fees.

Resolution & payout

Settlement runs on-chain. Polymarket's contract logic separates YES and NO shares as conditional tokens; at resolution the winning share lifts to $1.00 and the losing one to $0. The outcome input comes from the UMA Optimistic Oracle, which secures against bad resolution with a bond + dispute window.

Once finalised, the smart contract pays USDC to the holders' wallets within minutes — no withdrawal fees beyond Polygon network gas. Kalshi settles in USD via CFTC clearance, Betfair in account currency net of commission, Manifold in play-money mana with no cash-out.

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.

What does it cost to trade on PolyGram?

Zero. PolyGram 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.

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.