Alexi Giannoulias leads trader consensus at 57% for the February 2027 Chicago mayoral election, reflecting his substantial fundraising edge exceeding $22 million, union endorsements, and high name recognition after his August 2026 campaign launch. Incumbent Brandon Johnson formally entered the race on September 13 amid low approval ratings near 30% and limited campaign cash, while a crowded field including Susana Mendoza at 12.5% and more than a dozen other declared candidates fragments support. The nonpartisan race structure, with a potential April runoff if no one reaches a majority, keeps probabilities tight as early polling and petition drives highlight competition over public safety, fiscal pressures, and economic growth. Upcoming petition deadlines in October and continued fundraising will likely influence positioning before the first-round vote.