Will Mike Rounds be the Republican nominee for Senate in South Dakota?

Mike Rounds is priced at an exceptionally high 95¢ on Polymarket, reflecting near-certainty of his Republican nomination, though a notable 4¢ gap exists versus Kalshi's 91¢ pricing that suggests some cross-venue arbitrage opportunity. The extreme 9,956.9% implied yield on "No" reflects the illiquidity and low open interest ($11,045), with zero 24-hour volume indicating this market has stalled despite 70 days to expiration. The modest 2¢ spread and neutral regime mask underlying fragility—the cliff risk index of 19 suggests potential for sharp repricing if unexpected primary challengers emerge or Rounds faces unforeseen complications.

Resolution rules

This market will resolve according to the winner of the Republican Primary for United States Senator from South Dakota. If no 2026 South Dakota Republican Senate Primary takes place, this market will resolve to "Other". The resolution source for this market will be the first announcement of the results from the South Dakota Republican party, however an overwhelming consensus of credible reporting may suffice.

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