Recent polls for São Paulo’s two Senate seats show a fragmented field ahead of the October 4 first-round vote, with Simone Tebet and Marina Silva holding narrow leads in intention surveys while Guilherme Derrite, André do Prado, and Ricardo Salles remain within striking distance. High undecided shares, low single-digit support for most other registered candidates, and the mechanics of voters selecting two names keep first-place probabilities tightly bunched in trader pricing. Official campaigning has only recently begun, limiting differentiation so far. Further poll releases, candidate debates, major endorsements, or shifts in party alliances could quickly widen gaps by clarifying voter preferences among the leading contenders.