**Trader consensus centers on 78-80% turnout for Brazil’s October 25 presidential runoff, closely tracking the first-round figure of 78.92% recorded by the TSE on October 4.** High abstention of 21.08%—the highest in a presidential first round since 1998—left roughly 33.4 million eligible voters at home amid an older electorate, voter fatigue, and low penalties for non-participation. The tight contest between Flávio Bolsonaro and incumbent Luiz Inácio Lula da Silva, with most post-first-round polls showing a narrow edge for Bolsonaro, could encourage mobilization of swing and previous non-voters. Scheduled debates and TSE outreach may provide modest upward pressure, while structural demographic trends and polarization support continuity near recent levels rather than a sharp shift.