In the open-seat race for Massachusetts' 6th Congressional District Democratic primary on September 1, 2026, trader consensus favors Dan Koh at 74% due to his record-breaking early fundraising—over $2 million, more than any prior Massachusetts House candidate—and high-profile endorsements from former Rep. John Tierney, ex-Boston Mayor Marty Walsh, Transportation Secretary Pete Buttigieg in late February, and Foreign Policy for America last week. These developments have solidified his frontrunner status in a crowded field of over 10 candidates following Seth Moulton's Senate bid. Kevin Larivee trails at 25% on perceived local appeal, while others like Moulton linger at low odds amid fragmented opposition and no recent polls. Local pushback against perceived national meddling adds uncertainty.