SE Palmeiras vs. Club Cerro Porteño Arbitrage Leads Gaps at 1076% But Faces Expiry Dead Ends

Arbitrage opportunities between Polymarket and Kalshi are displaying highly distorted paper yields today, but execution reality requires caution. High headline returns are heavily impacted by zero reported volume and critical structural mismatches. ### The Expiry Dead Ends: Palmeiras and Lillestrøm The top-rated arbitrage on SE Palmeiras vs. Club Cerro Porteño boasts a theoretical 1076.47% net profit (Polymarket YES at 7.5¢ vs. Kalshi NO at 1.0¢). However, today is June 20, 2026, and both contracts have already passed their expiry dates (Polymarket expired May 21; Kalshi expired June 4). Similarly, the Lillestrøm SK vs. Kristiansund BK spread (589.66% net profit) expired in March and June. These are dead markets with zero liquidity; do not attempt to route capital here. ### The Active Risks: Florida Gov and French Elections For active books, the Florida Governor Republican Primary contract on Byron Donalds presents a 733.33% paper gap (Polymarket NO at 6.0¢ vs. Kalshi YES at 6.0¢). The execution blocker here is a major one-year expiry mismatch: Polymarket settles on August 18, 2026, while Kalshi settles on August 18, 2027. Trading this exposes you to a 12-month delta risk window. The French Presidential Election contracts on Jean-Luc Mélenchon (709.72% gap) and Gabriel Attal (678.21% gap) also suffer from a 13-month settlement mismatch. Polymarket resolves in April 2027, whereas Kalshi extends to May 2028. Unless you are prepared to carry unhedged exposure during these gap periods, these spreads are un-executable for pure arbitrageurs.