01.Massachusetts has the lowest state estate-tax exemption in the US: $2M.
Massachusetts is one of 12 states (plus DC) with a state estate tax — and the $2M exemption is the lowest in the country. Once an estate crosses $2M (which a Boston-metro house, a 401(k), and a brokerage account can easily do), Massachusetts taxes the ENTIRE estate from dollar one, not just the amount above the exemption. This is the most punitive state estate-tax structure in the US and the single highest planning priority for moderate-net-worth Massachusetts families.