PL maintains its position as the frontrunner for the largest bloc in Brazil’s Chamber of Deputies due to its expanded current caucus of roughly 100 seats following the April 2026 party-switching window, which allowed one in four deputies to change affiliations without penalty. This consolidation strengthens its organizational reach in the open-list proportional system ahead of the October 4 election, where alignment with the presidential candidacy of Flávio Bolsonaro further mobilizes evangelical, rural, and right-leaning voters. Traders price in continuity from these structural edges, while smaller federations such as FE Brasil and UPB face fragmentation risks in a polarized environment. No single late-breaking event has shifted the balance in recent weeks, though candidate endorsements and economic indicators through September could still influence final seat distributions.