Dan Koh's 72.5% implied probability as trader consensus frontrunner in the MA-06 Democratic primary stems from his dominant early fundraising—over $2 million raised, including January totals exceeding rivals' combined hauls—and high-profile endorsements from Pete Buttigieg, former Boston Mayor Marty Walsh, and IBEW Local 2222. The open seat, vacated by Rep. Seth Moulton pursuing a U.S. Senate bid, has drawn a crowded nine-candidate field for the September 1 primary, with Koh first to qualify on the ballot in late March by securing over 2,000 signatures. Mariah Lancaster trails at 7.6% amid fragmented support for challengers like Tram Nguyen and John Beccia, whose recent fundraising boasts have yet to close the gap. Ongoing forums and potential new endorsements could influence odds in this competitive race.