**Flávio Bolsonaro holds an 84% implied probability in the runoff against incumbent Luiz Inácio Lula da Silva following the October 4 first round, where the Liberal Party senator captured 47.03% of valid votes to Lula’s 45.16%.** Traders price the outcome heavily toward Flávio because no first-round runner-up has won the second round since Brazil’s return to democracy in 1985, and right-wing support is consolidating after smaller conservative candidates were eliminated. Recent developments include endorsements from Union Brasil and the Progressives (PP) for the October 25 runoff, alongside voter priorities on public security and economic conditions that favor the challenger’s platform. Lula’s position is further pressured by stagnant approval ratings and fallout from scandals such as the Banco Master investigation, which eroded institutional trust across the spectrum. These factors have driven the sharp shift in prediction-market pricing since the first-round results.