Incumbent U.S. Senator Ed Markey holds a commanding position in the Massachusetts Democratic Senate primary due to his long record of service since 1977 and established support among party voters. Recent Emerson College polling from early May shows Markey leading challenger Representative Seth Moulton 37% to 32% with nearly 30% undecided, narrowing an earlier 13-to-17-point advantage in April surveys. Moulton’s campaign emphasizes generational turnover and appeals to unenrolled voters, yet Markey’s higher name recognition and favorable image among likely Democratic primary participants continue to anchor trader assessments. Minor candidates including Representative Ayanna Pressley register negligible backing. With the September primary several months away, the market reflects the incumbent’s structural edge while accounting for Moulton’s incremental momentum in a contest still defined by undecided voters.