International Scientific Journals
of Scientific Technical Union of Mechanical Engineering "Industry 4.0"

This article presents a calculation model based on the impact of tourism services and income of hotel enterprises, which have a special share in this service, on the gross product, GDP, labor resources, capital investment and working capital through econometric models. It assesses labor resources, GDP, investment in fixed capital and key indicators for the development of the tourism complex of the Republic of Turkey and provides relevant forecasts. In addition, the statistical significance of the model based on the Eviews software package was checked and its suitability for forecasting purposes was determined.

The article proposes an approach to the formation of optimal investment portfolios according to the criteria of profitability and risk based on the predicted returns of assets obtained using fractal econometric models. It has been hypothesized that this method allows you to create more profitable and low-risk portfolios than in the optimization of historical returns. To test the approach and test the hypothesis, an attempt was made to form various portfolio options from the shares of two Russian issuers. The results obtained allow us to conclude that the proposed approach is promising, and further research is needed.

The postal services market is facing big challenges, both on global and national level. Besides e-substitution, a liberalization of the postal market contributes to the greater extent to this phenomenon. The purpose of this paper is to examine a state of the postal market in Serbia and main developments, considering a trend in the number of postal operators, number of services, service diversification, relation between letter and parcel market, etc.