Brazil Q1 2026 GDP Arbitrage Leads Pack with 1,539% Spread

Arbitrage spreads are widening across macro, political, and sports markets, but execution requires navigating extreme liquidity constraints and settlement mismatches. The top gap is in the Brazil Q1 2026 GDP market, offering a theoretical 1,539.34% net return. Polymarket's '<0.7% (YES)' contract is trading at an underpriced 0.3¢, while Kalshi's 'Above 0.5% (NO)' contract sits at 5.8¢. However, note the mismatch: Polymarket settles on May 29, 2026, while Kalshi locks funds until June 30, 2026. If the final print lands between 0.5% and 0.7%, both sides pay out, but the execution window is highly illiquid with zero reported daily volume. A similar duration mismatch plagues the Malta Parliamentary Election market. Polymarket's 'Labour Party (YES)' for 3rd place is priced at 0.1¢ (expires May 30, 2026), while Kalshi's 'NO' leg is priced at 7.0¢ but doesn't expire until May 30, 2027—representing a 12-month capital lockup. For the Alabama Senate markets (Hudson and Moore) and the Palmeiras vs. Cerro Porteño matchup, check settlement states immediately. Several Polymarket contracts list expiration dates that have already passed (May 19 and May 21), meaning these markets are likely already settled, rendering new arbitrage legs unviable despite the wide paper spreads.