G10 - General Financial Markets: General (includes Measurement and Data)Return

Green finance is becoming increasingly important today, affecting many areas of the economy. In this regard, the examination of green bond markets is becoming more and more important, as various financial shocks have also led to significant changes in the financial markets and economic policy processes. However, only a few of these new financial assets were issued on the emerging EU market, therefore the side effects of them have not yet been fully explored. In addition, the rise of green finance is only in its infancy in smaller economies, in various financial markets, which may be important to monitor in future investment decisions. The aim of our study was to examine the volatility properties of green sovereign bonds of European small open economies for the period between 2016 and 2021, where we analysed how the differences of these green sovereign bonds to conventional sovereign bonds changed over time. Also, we wanted to test whether there was a possibility of a conditional volatility premium for green government bonds. To answer our research questions, we calculated conditional volatilities, and the green premiums towards their standard forms using GARCH models. Our result suggested that the Polish and Hungarian green sovereign bonds have higher volatility than the traditional ones, which is the opposite of the German experience.

In this paper we analyse a temporal evolution of the Hurst exponent estimated on hourly returns of intraday electricity prices in the Czech Republic in 2017 and 2018. Firstly we used the log-returns with adjustments due to negative values, and secondly we employed the returns based on the area hyperbolic sine transformation. We implemented a sliding window technique in order to estimate the Hurst exponent using the Detrended Fluctuation Analysis method on subsamples with four distinct window sizes. According to the stylised facts of electricity, the spot prices and their corresponding logarithmic returns should be mean-reverting. Since the Czech intraday electricity market remains mostly unexplored, we examined this phenomenon on the intraday rather than on the spot market. Consequently, our analysis showed that the estimated values of Hurst exponent indicate a mean-reverting process for time scales greater than 24 hours and a weakly mean-reverting process for the shorter time scales. There were a few exceptions, though, since our calculations have revealed the presence of a nearly random or even weakly persistent behaviour on the shorter time scales.

Self-influence and self-reference are among the largely omitted, but quite substantial properties of thought systems in social sciences. These can have significant impact on the ways we can test such thought systems (theories), their applicability and reliability. This paper defines the basic terms of self-influence, which contrary to self-reference, is sneaky and demonstrates in practice over longer periods of time. The outline of classification of self-influence presented in this paper draws on notorious examples - CAPM and efficient market hypothesis. These examples show that philosophy has still much to tell about the methodology of science in economics.