Dan Koh leads the MA-06 Democratic primary with 77% implied probability due to a commanding position in the latest polling and a substantial fundraising edge. An early August survey showed Koh at 34% among likely Democratic voters, nearly 20 points ahead of John Beccia and Tram Nguyen. Koh’s prior federal roles, including in the Biden administration, combined with roughly $3.6 million cash on hand and broadcast advertising, have solidified his frontrunner status ahead of the September 1 primary. State Representative Tram Nguyen remains the clearest alternative at 18%, drawing support from her legislative record and community ties, while Beccia and lower-polling candidates trail far behind. The race centers on name recognition, resources, and voter consolidation in the final weeks.