**Traders assign a 71% implied probability to "Yes" on any candidate receiving the most votes ever in a Brazilian presidential runoff.** The October 4 first round produced record-level absolute votes, with Flávio Bolsonaro at 56.1 million (47.03% of valid ballots) and incumbent Lula at 53.8 million (45.16%), both advancing to the October 25 second round after no candidate reached a majority. These totals already approach or exceed prior first-round benchmarks, and historical runoff patterns show substantial consolidation of votes from eliminated candidates plus higher mobilization. With registered voters near 159 million and recent turnout around 79%, a polarized contest between the leading contenders creates conditions for one side to surpass the previous second-round record of roughly 60.3 million votes set in 2022. The narrow first-round margin and strong regional bases for both candidates further support elevated absolute participation in the runoff.