Recent first-round results placed Douglas Ruas (PL) at 49.27% and Eduardo Paes (PSD) at 42.76% of valid votes, with Anthony Garotinho (Republicanos) at 3.17%, triggering a second round on October 25 pending TSE review of Garotinho’s candidacy. Pre-election polling showed Paes maintaining a narrow lead that narrowed as Ruas gained ground through direct voter outreach and PL backing, while both candidates drew significant rejection levels near 45-50%. High first-round abstention above 23% and undecided blocs from eliminated candidates create volatility in runoff turnout and vote migration. These factors sustain tight trader pricing across margin outcomes, with any shift in Garotinho’s eligibility or late mobilization of swing voters in key municipalities likely to determine separation between the contenders.