Mamdani, elected New York City mayor after his 2025 Democratic primary upset over Andrew Cuomo, has endorsed a slate of progressive congressional candidates—including Brad Lander, Claire Valdez, and Darializa Avila Chevalier—for the June 23, 2026, New York primaries. With early voting underway and Senator Bernie Sanders scheduled to join a get-out-the-vote rally, traders price the chance of a full sweep at even odds due to Mamdani’s demonstrated voter mobilization alongside countervailing factors such as entrenched incumbents, split Democratic endorsements, and variable turnout in the targeted districts. Recent polling gaps, fundraising differentials, and the scale of progressive versus moderate participation in the final days of early voting could shift implied probabilities in either direction before results are certified.