The technical consultants for the BETA: Commercial Buildings Pilot program (Slipstream and their sub-consultant team) prepared a market characterization of the commercial and multifamily building stock in Massachusetts. The summary report contains a wealth of information about building use types, sizes, vintages, types of HVAC and hot water systems, types of fuels used, and more. The report pays particular attention to buildings in Environmental Justice communities. The data presented are organized is ways that highlight decarbonization opportunities. In combination with the priorities of the Pilot program, the report is intended to help focus program design on developing resources for the decarbonization of commercial and multifamily buildings statewide.