Dan Koh leads trader consensus in the MA-06 Democratic primary at 73% due to his prior federal experience as deputy director of the White House Office of Intergovernmental Affairs, local service as an Andover selectman, and early endorsements from North Shore officials, alongside being the first candidate to qualify for the September 1, 2026 ballot. The open seat created by incumbent Seth Moulton's Senate challenge has produced a crowded field of more than a dozen Democrats, yet no rival has consolidated comparable name recognition or resources. State Representative Tram Nguyen holds the next-highest share at 25% amid an April poll showing a statistical tie, while remaining contenders including Kevin Larivee and Rachel Creemers register lower probabilities reflecting fragmented support in the three months before primary voting.