The last decade has seen the emergence of alternative sources of early-stage finance, which are radically changing and reshaping the start-up eco-system. These include incubators, accelerators, science and technology parks, university-affiliated seed funds, corporate seed funds, business angels - including "super-angels", angel groups, business angel networks and angel investment funds - and both equity- and debt-based crowdfunding platforms. In parallel with this development, large financial institutions that have traditionally invested in late-stage and mature companies, have increasingly diversified their investment portfolios to "get into the venture game", in some cases, through the traditional closed-end funds model and, in other cases through direct investments and co-investments alongside the closed-end funds. This paper reviews the main features, investment policies and risk-return profiles of the institutional and informal investors operating in the very early stage of the life cycle of entrepreneurial firms. It concludes that traditional closed-end venture capital funds continue to play an important role in early stage finance because of their unique competences (e.g. screening, negotiating and monitoring) in what has become a wider and more complex financing ecosystem.