There has been a subtle, but insistent shift in the way a growing number of charities are looking to allocate their capital. We are finding an increasing recognition that investment should have purpose as well as generating profit, with the charity sector at the vanguard of this change. While there are an increasing number of quoted funds claiming to be impact investment driven, they are often stretching what we think of as the true definition of impact. These funds can still offer desirable benefits, but the private market is where we see most impact activity. This article addresses the issues for charities wishing to venture into private environmental and social impact investments.