Arizona Diamondbacks vs. Seattle Mariners

Platform comparison

Active sub-markets

Market context

The Arizona Diamondbacks face the Seattle Mariners in an MLB regular-season matchup scheduled for 31 May at 4:10PM ET. The current crowd-implied probability of 14% for a Diamondbacks victory reflects substantial market confidence in a Mariners win, though this represents a relatively tight matchup in absolute terms given the early-season timing and both teams' competitive positioning within the AL West and NL West respectively.

Historical performance between these franchises shows the Mariners have maintained a slight edge in recent seasons, though regular-season baseball exhibits high variance and single-game outcomes frequently diverge from season-long trends. The 14% probability assigned to Arizona suggests the market is pricing in Seattle's recent form, potential pitching matchup advantages, or roster depth considerations. Comparable regular-season games between evenly-matched division rivals typically settle in the 40–60% range for the favoured side; the pronounced skew here indicates specific factors are driving the Mariners preference rather than general uncertainty.

Traders should monitor pitching assignments and any late roster changes announced in the days preceding the fixture. Weather conditions at the scheduled venue and any injury updates to key position players could shift the probability meaningfully. Recent team performance metrics, including run differential and bullpen effectiveness, often correlate with single-game outcomes more reliably than season-long records. The settlement window extends to 7 June, allowing for postponement resolution should weather or scheduling conflicts arise.

Methodology

This page tracks Arizona Diamondbacks vs. Seattle Mariners across four political prediction venues. Live odds come from the Polymarket order book (the deepest political prediction-market book). Kalshi is the CFTC-regulated US alternative, Betfair the established UK sports-exchange with politics markets, Manifold the open play-money variant. Election Predictions UK routes every trade through to Polymarket — at 0% fees.

Resolution & payout

Political markets typically settle on official candidate or agency confirmation. Polymarket uses UMA Optimistic Oracle: a proposer posts the outcome with a bond, the two-hour window opens, then the smart contract pays USDC.

Kalshi settles USD via CFTC clearinghouse, with clearly defined resolution sources (e.g. AP race calls for elections). Betfair settles after the official outcome is registered with the league or agency. Manifold is play-money.

FAQ

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 Election Predictions UK?

Zero. Election Predictions UK routes every order to the live Polymarket order book; the only cost is the Polygon network fee, typically under $0.01 per transaction.

Do I need to KYC for this market?

Not under $1,500 of lifetime trading volume. Above that threshold, Election Predictions UK 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.