Analysis of Scientific and Methodical Approaches to Portfolio Investment as a Tool of Financial Provision of Sustainable Economic Development

The article analyses scientific and methodical approaches to portfolio investment. It develops recommendations on specification of the categorical apparatus of portfolio investment in the context of differentiation of strategic (direct) and portfolio investments as alternative approaches to the conduct of investment activity. It identifies the composition and functions of objects and subjects of portfolio investment under conditions of globalisation of the world financial markets. It studies main postulates of the portfolio theory and justifies a necessity of identification of the place, role and functions of subjects of portfolio investment in them for ensuring sustainable development of the economy. It offers to specify, as one of the ways of further development of portfolio theories, a separate direction in the financial provision of economy with consideration of ecologic and social components - socio responsible investment.