Dan Koh leads the MA-06 Democratic primary field with 75.5% implied probability due to his commanding fundraising edge—raising roughly $4.5 million with millions in reserves—and sustained television advertising that highlights his prior roles in the Biden administration and opposition to the current president. Recent internal polling shows him at 34% support with a 19-point advantage over rivals, consistent with trader consensus in the closing weeks before the September 1 primary. State Representative Tram Nguyen, at 16.5%, draws from her legislative record and personal background but trails significantly in spending and media presence. The remaining candidates, including John Beccia and others under 3%, face structural barriers from limited visibility and resources in a race centered on affordability, federal experience, and Democratic turnout dynamics.