Jon Ossoff leads trader expectations to top Democratic presidential nomination prediction markets by October 31 due to sustained inflows into his contracts on major platforms and his positioning as a swing-state senator with cross-faction appeal. Recent polling averages show Kamala Harris ahead nationally, yet markets have elevated Ossoff and Alexandria Ocasio-Cortez above Gavin Newsom and others in implied probabilities, reflecting trader focus on name recognition, Senate reelection visibility, and early positioning ahead of 2028. Ossoff has repeatedly stated he has no interest in a presidential bid and remains focused on Georgia, while no major candidate has formally declared. Upcoming midterms and any shifts in polling or market volume could still alter the short-term leader before the snapshot date.