**Ruccy Judith Oscco Polar leads the Arequipa mayoral market at 40.5%** after assuming the provincial mayoralty in May 2026 following the JNE-mandated vacancy of Víctor Hugo Rivera Chávez over contracting restrictions tied to his pet. As the sitting officeholder who has since registered her candidacy, Oscco benefits from incumbency visibility and administrative continuity ahead of the October 4 vote. A crowded field of roughly two dozen registered contenders fragments support, keeping implied probabilities tightly bunched among the next tier of candidates in the mid-30s. Recent local polling snapshots and candidate registration filings show no decisive breakout, with trader pricing reflecting the structural challenge of building a majority in Peru’s multi-candidate municipal contests. Developments that could widen gaps include clearer polling trends, major endorsements, or visible administrative actions by the current mayor in the remaining weeks.