Seattle Mariners vs. Kansas City Royals

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Active sub-markets

Market context

The Seattle Mariners travel to Kansas City on 24 May for a regular-season MLB fixture at 2:10 PM ET. The market currently implies an 11% probability of a Mariners victory, reflecting the Royals' home-field advantage and recent form. Resolution depends on official MLB final statistics; postponement extends the settlement window to 31 May, whilst cancellation or a tied result triggers a 50-50 split.

Prediction markets on individual baseball games have historically tracked close to closing-line value when teams are evenly matched, but diverge significantly when one side carries structural advantages—home teams win roughly 54% of MLB games across seasons. The 11% probability assigned here suggests market participants view Kansas City as substantial favourites, a positioning that typically reflects pitching matchups, recent win-loss records, and injury status rather than pure home-field effect alone. Comparable single-game markets show that probabilities below 15% for the underdog often compress slightly in the final hours as information crystallises.

Traders should monitor roster announcements through 24 May, particularly starting pitcher confirmation and any late-inning bullpen availability. Weather conditions at Kauffman Stadium—wind direction and temperature affect fly-ball carry—merit attention given the venue's dimensions. The market operates under UK regulatory frameworks; German GlüStV provisions do not apply to UK-domiciled platforms, whilst CFTC reach remains limited to US persons engaging in derivatives contracts. No-KYC access up to £1,200 (approximately $1,500) means casual traders can participate without identity verification below that threshold, though larger positions require standard verification procedures.

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

Polymarket-based markets settle through the UMA Optimistic Oracle on Polygon. A proposer submits the outcome, a two-hour challenge window opens, and unchallenged proposals finalise the resolution. Payouts settle automatically in USDC the moment the result is final — no bookmaker, no delay.

Kalshi-based markets settle in USD via the CFTC-regulated clearinghouse. Betfair Exchange settles in GBP/EUR net of commission. Manifold is play-money and does not pay out real funds.

FAQ

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 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 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.