South Carolina Senate Special Republican Primary: First Round Winner

Platform comparison

Market context

Polymarket prices this contract at **0% YES** today, so the market is effectively saying the first-round Republican winner in South Carolina’s special Senate primary is not yet being priced as settled and there is no live bid for that named outcome on-chain. The market resolves on the candidate with the most valid votes in the first round on the Polygon-based, USDC-settled conditional token market, with any runoff on 25 August irrelevant unless first-round vote totals are tied or revised.

The clearest historical guide is the 2026 Republican primary already held for South Carolina’s Senate seat, where Lindsey Graham won outright with **56.8%** and a wide margin over his nearest challenger, Mark Lynch, while the field still produced a meaningful second place and a long tail of minor candidates.[1][4][7] That matters for traders because South Carolina Republican Senate primaries have often been decided by the top line rather than by runoff drama, but the special-election setup keeps first-round plurality mechanics in play if the candidate slate is split more sharply than in the regular primary.[5][16] In that sense, a 0% market reading is less a forecast of the underlying race than a sign that the contract has not yet been repriced around the eventual vote distribution.

What to watch now is whether any candidate withdrawals, endorsements, or ballot-access changes shift the vote split before election day, alongside SC Votes’ notice that early voting and the runoff timetable are already fixed.[5][18] Recent live coverage from AP, NBC, and The New York Times shows the June primary results were fully reported and projected quickly, which gives traders a benchmark for how fast first-round data may hit the tape on 11 August and how quickly the conditional token should reprice once counties start reporting.[2][4][7]

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). 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

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.

UK Frequently Asked Questions

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.

Is Polymarket legal in the UK?

Polymarket is accessible to UK traders but is not UKGC-licensed. It operates under US CFTC jurisdiction. UK residents face no domestic legal prohibition on using it, but UKGC consumer protections do not apply. For UKGC-regulated alternatives, Betfair Exchange and Smarkets offer similar prediction-style markets.

Do I pay tax on prediction market profits in the UK?

UKGC-licensed platform profits (Betfair, Smarkets) are typically tax-free gambling winnings for UK individuals. Polymarket profits involve USDC crypto transactions, which HMRC treats as Capital Gains Tax events. Keep full transaction records and report via Self Assessment if gains exceed £3,000 per tax year.

How do I deposit on Polymarket from the UK?

UK traders typically fund Polymarket via Coinbase UK, Kraken or Revolut — buying USDC with GBP and transferring to a Polygon-compatible wallet (MetaMask, Coinbase Wallet). Polymarket's onboarding walks you through the bridging process. Typical GBP-to-USDC conversion costs 0.5–1%.