KY-04 Republican Primary: Margin of Victory

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Market context

Polymarket is pricing this Kentucky 4th District Republican primary margin contract with the market effectively shut at a 0% YES probability, even though the underlying vote took place on 19 May and the market’s settlement window closed at 00:00 UTC that day. On Polymarket, traders post USDC on Polygon against conditional tokens tied to the final certified margin, so the relevant question is not the winner alone but the size of the top-two gap. With the market now at zero, the contract is treating the published race shape as fully reflected in the tape rather than leaving room for a late change.

For context, margin markets in low-turnout primaries often move sharply once precinct-level reporting starts, because a small swing in rural or suburban precincts can quickly change the band a result lands in. Polymarket’s own pricing on 20 May pointed to a dominant Gallrein win band, with “Gallrein 9%+” listed as the clear frontrunner and “Gallrein 6-9%” far behind, which is consistent with a race expected to clear the lower margin buckets. Comparable congressional primaries have tended to resolve cleanly once the first tranche of results establishes whether the contest is a blowout or merely a comfortable win, leaving little value in the narrower bands.

A trader watching this market would still focus on certification timing, any delayed county returns, and whether local election officials update or correct unofficial totals. Any late absentee, provisional, or canvass adjustments matter only if they alter the first- and second-place percentages enough to move the absolute margin into a different bucket. The key catalysts are therefore not campaign messaging now, but election-board reporting schedules, county canvass releases, and any official tabulation updates from Kentucky election authorities.

Sources: 1 · 2

Methodology

This page reviews KY-04 Republican Primary: Margin of Victory 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

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?

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.

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.

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.

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.