In the open Massachusetts 6th Congressional District Democratic primary set for September 1, trader consensus heavily favors Dan Koh at 76.5% implied probability, driven by his dominant ActBlue fundraising—over $311,000 in February alone—first-to-qualify ballot status with over 2,000 signatures last week, and fresh endorsements like Swampscott Select Board Vice Chair Doug Thompson's on April 1. Incumbent Seth Moulton’s Senate challenge against Ed Markey leaves a crowded field of nine Democrats, with Mariah Lancaster and Tram Nguyen gaining traction via early entries and fundraising touts, though self-funder John Beccia’s recent $2 million infusion has yet to shift odds significantly. Absent polls, upcoming town caucuses and signature deadlines loom as key catalysts.