Boston Red Sox vs. Kansas City Royals

Platform comparison

Active sub-markets

Market context

Boston and Kansas City were scheduled to meet on 19 May at Kauffman Stadium, and the game has already been played. The key factual point for the market is that the Red Sox won 3-1, so a zero-cent YES price was not consistent with the eventual result and likely reflected stale pricing rather than a genuine view on the teams.

Recent comparable results between the sides were mixed but competitive. Boston had taken an early-season win in the series, with reports of a 10-1 victory and later a 9-5 and 8-5 win in 2025, before Kansas City responded with a 7-3 result on 6 August. That kind of split head-to-head record usually supports moderate rather than extreme pricing, especially when neither club is dominant overall.

The main market catalysts before first pitch were line-up and pitching updates, plus any weather or scheduling changes. Polymarket’s own market page noted injuries on both sides, including Boston catchers Connor Wong and Carlos Narváez listed day-to-day, and Kansas City missing Cole Ragans on the 15-day IL, with Jonathan India’s shoulder issue and Matt Strahm’s knee recovery also in view. The game was also linked to an earlier start because of weather concerns, so late confirmation of the line-up card and whether the opener went ahead on time were the practical drivers of settlement risk.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

Methodologically we separate two layers: the live probability (Polymarket mid-price) and the platform attributes (fee, KYC, settlement currency, payment rails). The odds column is filled only where we have clean data — that avoids the made-up numbers that get a network demoted when search engines cross-check against the source venue.

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

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.

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.