The Côte-du-Sud riding features a tight three-way contest among incumbent Mathieu Rivest of the Coalition Avenir Québec, Valérie Hamel of the Parti québécois, and Frédéric Poulin of the Parti conservateur du Québec, with Nancy St-Pierre of the Parti libéral du Québec trailing. Recent candidate confirmations and the launch of the provincial campaign in late August have kept the outcome uncertain, as local polling aggregates show the top three parties separated by just a few points in vote intention. Regional priorities such as health care access, agricultural supports, and decentralized services align with Hamel’s background and Poulin’s profile, while Rivest benefits from incumbency but faces provincial headwinds for his party. Traders reflect this balance through closely matched implied probabilities, with separation likely to emerge from turnout patterns, late-campaign events before the October 5 vote, or clearer signals on which opposition party consolidates anti-CAQ support.