Dan Koh's commanding fundraising edge, including over $2 million raised by late 2025 and $204,000 in January alone—far exceeding rivals—combined with being the first candidate to secure ballot access through signatures, has established him as the clear frontrunner in the open Massachusetts 6th District Democratic primary. The seat opened after incumbent Seth Moulton launched a Senate challenge. Early 2026 polls showed a fragmented field with Tram Nguyen, John Beccia, and others competitive amid high undecideds, yet recent local endorsements and resource disparities have shifted trader consensus toward Koh at 73.5% implied probability. September 1 primary timing leaves room for further movement from campaign events or additional polling.