Dan Koh leads the Massachusetts 6th Congressional District Democratic primary field with substantial trader support due to his commanding fundraising edge, including over $4.5 million raised and $3.6 million cash on hand, enabling sustained broadcast and cable advertising. Recent internal polling from late July and early August shows him at 34 percent among likely voters, roughly double the support for state Rep. Tram Nguyen or John Beccia. Nguyen maintains a secondary position through her legislative record and targeted messaging on personal background. The September 1 primary date concentrates attention on these late-cycle dynamics, with lower-polling candidates facing resource and visibility constraints that limit shifts in the current consensus.