Coppejans vs Den Ouden

This market covers a professional tennis match between Kimmer Coppejans and Guy Den Ouden, listed on both Kalshi and Polymarket. The two platforms frame the fixture slightly differently: Kalshi identifies it as a 2026 ATP Challenger Liege quarterfinal scheduled for July 10, resolving Yes if Coppejans wins after a ball has been played, while Polymarket lists it as a Bunschoten match originally scheduled for July 18, resolving to whichever player advances. In both cases, the outcome hinges on who wins the head-to-head. The pricing picture is sharply split. On Kalshi, where volume sits near $1.29M, Coppejans is priced at 99.0% and Den Ouden at just 1.0%, making Coppejans a heavy favourite. Polymarket, which has effectively no volume on its version, shows the market roughly untraded at 50.5% for Den Ouden and 49.5% for Coppejans, alongside a separate Yes/No pair at 50.0% each. That produces a striking 49.5-point cross-platform spread on both players, driven almost entirely by Polymarket's inactive, near-default pricing against Kalshi's liquid, one-sided line pointing to Coppejans.