Improving the Quality of Modeling the Efficiency of Managing Portfolios of Polish Open-ended Investment Funds in 2018-2021.

The paper examines investment efficiency of Polish open-ended mutual funds in the period before and during a pandemic. For this purpose the Trynor-Mazuy model, estimated for two periods of one and a half years was used. On this basis, various aspects of portfolio management of equity, balanced, stable growth and bond funds were evaluated. In particular, the skills of selecting assets for portfolios, market timing and following the market trend were assessed. The influence of volatility on fund performance was also taken into account by examining the ARCH effect and constructing GARCH models. At the same time, the improvement of the quality of market timing modeling was assessed [ABSTRACT FROM AUTHOR]