Considering the difficulty that sustainable ventures have in obtaining financing, this work intends to conceive the way in which impact investors decide on the allocation of financial resources. The methodology adopted is based on a qualitative analysis of 25 case studies by applying grounded theory. The results indicate that impact investors consider both objective and subjective elements of decision, which is in line with a conventional risk analysis process. Finally, a set of criteria for granting impact investments is outlined to serve as a guide for those sustainable entrepreneurs seeking financial support.