Former state Representative Reilly Neill commands 91.5% implied probability on Polymarket as the Montana Democratic U.S. Senate primary frontrunner ahead of the June 2 vote, reflecting her superior fundraising—over 75% of the field's cash on hand—paired with legislative name recognition and recent media appearances, including a May 8 radio Q&A and NBC Montana interview. A GOP super PAC mailer last week labeling her "too liberal for Montana" underscores trader consensus on her nomination lock in this low-turnout primary, where challengers Alani Bankhead, Michael BlackWolf, Michael Hummert, and Kathleen McLaughlin lack comparable resources or momentum despite a recent debate. Upsets could stem from a late major endorsement, scandal, or unusual crossover voting, though historical primary base rates favor established candidates.