Seattle Mariners vs. New York Yankees

Platform comparison

Market context

The Seattle Mariners travel to face the New York Yankees on 13 August at 1:35 PM ET in a regular-season matchup. Polymarket currently prices a Mariners victory at 41%, reflecting the Yankees' status as home favourites in this American League East contest. The conditional token structure on Polygon settles against official MLB final statistics, with the market remaining open through 20 August should postponement occur.

Historical matchups between these franchises show the Yankees have maintained a slight edge in recent seasons, though the Mariners' 2022–2023 competitive window produced several notable victories. The Yankees' home record typically outperforms their road performance, and August baseball often favours teams with deeper bullpen resources. Current season standings and wild-card positioning will influence both squads' tactical approaches, particularly regarding pitcher usage and lineup construction. The 41% probability assigned to Seattle suggests traders view the Yankees' home-field advantage and roster depth as material factors, though not prohibitively so.

Traders should monitor starting pitcher announcements, which typically confirm 48 hours before first pitch. Recent injury reports from both organisations matter considerably—the Yankees' depth at key positions and the Mariners' outfield availability could shift market pricing materially. Weather conditions at Yankee Stadium on game day may favour either team's style; August heat occasionally amplifies home-run distances. Any roster moves or unexpected roster decisions announced between now and 13 August will likely trigger repricing, as will updated playoff probability models that affect team motivation levels in late regular-season play.

Methodology

Methodologically we separate two layers: the live probability (Polymarket mid-price) and the platform attributes (fee, KYC, settlement currency, payment rails). That keeps the comparison honest — a single canonical probability across the row, with the venue-by-venue trade-offs spelt out in the columns next to it.

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

Where can I trade this market with the lowest fees?

Polymarket is geo-blocked in the US/UK/EU. The easiest 0%-fee broker into the same order book is PolyGram. Kalshi charges up to 7% per trade; Betfair Exchange takes 2-5% commission on net winnings.

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 Polymarket cost to trade?

Polymarket itself charges 0% — the only cost is the Polygon network fee, typically under $0.01 per transaction. Off-chain venues like Kalshi or Betfair charge 2-7% commission.

Do I need to KYC for this market?

On Polymarket directly, no — it's wallet-based. Intermediary brokers like PolyGram trigger KYC only above $1,500 of lifetime trading volume; under that you trade pseudonymously with a single wallet address.

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.