Marília Arraes (PDT) holds a clear lead in trader consensus for first place in Pernambuco’s October 4 Senate election, reflecting her consistent edge in late-September polling. Recent Datafolha and Quaest surveys place her at 18–19 percent, ahead of Humberto Costa (PT) at 14–17 percent and Mendonça Filho (PL) at 10–13 percent, with Eduardo da Fonte (PP) and Túlio Gadêlha (PSD) further back. Arraes benefits from her alliance with ex-Recife mayor João Campos in the Frente Popular coalition, which consolidates support across key voting blocs. High undecided and blank/null shares (around 30–40 percent combined) keep the second seat more open, but her stable first-place margin in multiple recent field tests underpins the elevated implied probability for top finish. No major campaign events have shifted these dynamics in the past week.