Palmeiras vs. Cerro Porteño Leads Cross-Venue Gaps; Liquidity Remains Thin

Theoretical cross-venue arbitrage spreads between Polymarket and Kalshi remain historically wide, but execution reality is highly constrained by illiquidity and structural mismatches. ### 1. SE Palmeiras vs. Club Cerro Porteño The widest theoretical spread is on the Palmeiras vs. Club Cerro Porteño matchup. Polymarket is pricing Cerro Porteño (YES) at 7.5¢, while Kalshi offers Cerro Porteño (NO) at 1.0¢. Total cost to lock in both sides of the contract is 8.5¢, offering a theoretical net profit of 1076.47% ($5,382 return on a $500 total allocation). Note the severe execution risk: there is no reported volume, and the contract expiration dates (Poly: May 21, 2026; Kalshi: June 4, 2026) are both in the past relative to today's date (June 22, 2026). This indicates unresolved settlement or stale order books. Do not deploy capital here without verifying manual settlement conditions. ### 2. Florida Governor Republican Primary Byron Donalds (NO) is priced at 6.0¢ on Polymarket, while Kalshi is trading Donalds (YES) at 5.0¢. Lock-in cost is 11.0¢ for a 100¢ payout, translating to an 809.09% return. No volume has been reported on either side, meaning slippage will be severe if trying to size up. ### 3. French Presidential Nomination (Jean-Luc Mélenchon & Gabriel Attal) Two French election run announcements offer high theoretical yields. Jean-Luc Mélenchon (NO) at 1.4¢ on Poly vs. (YES) at 10.0¢ on Kalshi yields 781.06%. Gabriel Attal (NO) at 7.4¢ on Poly vs. (YES) at 5.5¢ on Kalshi yields 672.20%. Both markets have long durations (expiring 2027/2028) and suffer from zero reported near-term volume. ### 4. China GDP Q2 2026 Polymarket's 4.0-4.3% (YES) at 1.2¢ and Kalshi's Above 4.0% (NO) at 13.0¢ show a theoretical 604.23% return. Warning: This is not a clean arbitrage. If China's GDP is reported at 4.5%, Kalshi's 'Above 4.0% (NO)' expires worthless, and Polymarket's '4.0-4.3% (YES)' also expires worthless. This structural gap carries absolute loss risk if GDP lands outside the 4.0-4.3% range.