Dan Koh leads the MA-06 Democratic primary field at 78.5% implied probability, driven by his substantial fundraising edge—roughly $3.6 million cash on hand—and sustained television advertising that highlights his prior congressional bid, White House experience, and opposition to the Trump administration. State Representative Tram Nguyen trails at 18%, bolstered by her current legislative record on affordability and housing plus targeted ads, yet remains well behind in recent internal polling showing Koh ahead by double digits. The September 1 primary date leaves limited time for shifts, with the rest of the field—including John Beccia, Mariah Lancaster, and Jamie Zahlaway Belsito—polling in the low single digits or below amid Koh’s resource advantage and name identification in a crowded contest focused on cost-of-living issues and Democratic opposition strategies.