Texas Republican Senate Primary Winner

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Market context

Texas Republicans are set to choose their nominee for the US Senate this month, with the runoff now the decisive stage after no candidate cleared 50% in the March primary. John Cornyn, the incumbent, led the first round narrowly on 41.9%, just ahead of Ken Paxton on 40.7%, while Wesley Hunt was a distant third on 13.5%. That split is the key comparison: in Texas runoffs, the first-round leader does not always hold once the race becomes a straight head-to-head, especially when the challenger is better aligned with the party’s activist base. But incumbency, statewide name recognition and institutional fundraising still matter, so the market has to balance a close primary finish against the usual advantage for an established senator.

The main near-term catalyst is Donald Trump’s endorsement of Paxton on 19 May, which has sharpened the party-line fight and, according to recent reporting and market commentary, improved Paxton’s standing heading into the 26 May runoff. Early voting is already underway, so the next meaningful signal will be turnout and any late county-level reports from the Texas Republican Party. The result should first be announced by the party, but a clear and consistent consensus from credible outlets would also be enough for settlement. Traders should watch whether Cornyn can hold traditional Republican voters in urban and suburban counties, or whether Paxton’s support among the more Trump-aligned base proves decisive in a low-information runoff.

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

Settlement runs on-chain. Polymarket's contract logic separates YES and NO shares as conditional tokens; at resolution the winning share lifts to $1.00 and the losing one to $0. The outcome input comes from the UMA Optimistic Oracle, which secures against bad resolution with a bond + dispute window.

Once finalised, the smart contract pays USDC to the holders' wallets within minutes — no withdrawal fees beyond Polygon network gas. Kalshi settles in USD via CFTC clearance, Betfair in account currency net of commission, Manifold in play-money mana with no cash-out.

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.

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.

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 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.