Flávio Bolsonaro’s first-round victory on October 4, securing roughly 47% of valid votes against incumbent Luiz Inácio Lula da Silva’s 45%, has driven trader consensus toward an 84% implied probability for the October 25 runoff. Right-wing candidates eliminated in the initial round are expected to consolidate support behind the Liberal Party senator, bolstering his position in a polarized contest marked by strong congressional and gubernatorial gains for conservative forces. Lula, seeking a fourth non-consecutive term at age 80, faces headwinds from voter fatigue and the migration of remaining ballots, though structural turnout dynamics and late-campaign developments could still influence final margins. Prediction markets reflect this post-first-round momentum in real-money assessments of runoff outcomes.