ANALYSIS OF THE MARKOWITZ’S AND TOBIN’S MODELS FOR SECURITIES PORTFOLIO CONSTRUCTION

The conclusions about the strata of society, various parties are supported by, have been made. The question arises of revising and improving the ways of forming the investment portfolio, since the degree of influence of macroeconomic indicators on the stock market behavior changes. The stock market is one of the key elements of the financial system of any state. The essence of the securities portfolio, the main task and the main objective of portfolio investment, the nature and methods of forming the securities portfolio in the conditions of instability of the Ukrainian stock market are considered. It describes the process of forming a securities portfolio, which is divided into five stages: determining investment objectives and priorities, conducting an analysis of securities, creating a portfolio and choosing management tactics, revising a portfolio and evaluating portfolio performance. On the basis of Markowitz’s model and Tobin’s model are developed algorithmic, informational and software. The applied capabilities of portfolio investment models are explored, which realize the main idea of Markowitz to form an optimal securities portfolio, while at the same time having fundamental differences. And the main difference Tobin’s model, which includes a certain risk-free asset, along with risky securities. An optimal securities portfolio is being built using ten risky stocks of various sectoral activities of Ukrainian enterprises using the Markowitz model and using risk-free assets (government corporate bonds) for the Tobin model. Also the composition, profitability and risk of the optimal portfolio in the Ukrainian stock market are determined. In addition, a graph of profitability and risk dependencies is constructed, where each point of the chart is a certain portfolio with a certain number of investments in the stocks of listed companies. The conclusion is made on the results obtained, focusing on their difference depending on the choice of the model of portfolio formation.