Trump-backed Alabama candidate's Senate runoff odds slide on Kalshi and Polymarket
Barry Moore's odds to win the Alabama Republican Senate runoff have fallen sharply on prediction markets in the run-up to the contest. On Kalshi, Moore's implied probability dropped from 91% on May 30 to about 79% as of Friday afternoon, according to Al.com. Polymarket is showing a similar pattern, with DeFi Rate pricing Moore at roughly 80-84%. The decline comes despite former President Trump's endorsement of Moore over Jared Hudson in the Republican primary race. The contest has drawn heavy betting volume as traders assess the durability of Trump's political influence in down-ballot races. The two-tiered pricing — with Kalshi near 79% and Polymarket slightly higher at 80-84% — leaves a modest but noticeable spread between the two venues.
Kalshi's 12-point drop on Moore exposes how quickly political prediction markets reprice when retail flow concentrates in a single endorsed candidate. Traders now face spread risk between Kalshi and Polymarket that institutional market makers like DRW, Wintermute and IMC could arbitrage if they deploy cross-venue infrastructure fast enough.
DRW, Wintermute and IMC join a growing roster of market makers building prediction-market infrastructure, with their new desks for Kalshi and Polymarket arriving just as traders are actively repricing high-profile political contracts like the Alabama Senate runoff.