The tight contest between incumbent Luiz Inácio Lula da Silva and Flávio Bolsonaro, who remain statistically tied in recent first-round polling around 37-42%, has fragmented the right-leaning electorate and elevated several center-right and independent candidates as plausible contenders for fourth place. Ronaldo Caiado, Renan Santos, and Augusto Cury lead market pricing for that position due to their consistent low-single-digit to mid-single-digit shares in surveys, combined with ongoing campaign activity, social media growth, and parallel debate efforts that sustain their visibility. High undecided and blank/null rates near 15% plus strategic "voto útil" messaging from Bolsonaro allies keep probabilities fluid, while late shifts from debate performances, endorsements, or turnout among younger or regional voters could consolidate or disperse support among the trailing field before the October 4 vote.