Persistence in the cryptocurrency market: does size matter?

The BCG Matrix was introduced almost 50 years ago, and is today considered one of the most iconic strategic planning techniques. Using management fashion theory as a theoretical lens, this paper examines the historical rise, fall and persistence of the BCG Matrix. The analysis highlights the role played by fashion-setting actors (e.g., consultants, business schools and business media) in the rise of the BCG Matrix. However, over time, portfolio planning models such as the BCG Matrix were attacked and discredited by a host of different actors, and gradually fell out of favor. Even though the BCG Matrix has fallen from grace, it is still alive and has left an imprint on management education and practice. Despite being largely discredited in academic circles, many practitioners still view it as an important corporate portfolio planning technique.

One of the pressing problems in the modern development of the world financial system is an excessive increase in state debt, which has many negative consequences for the financial system of any country. At the same time, special attention should be paid to developing an effective state debt management system based on its forecast values. The paper is aimed at determining the level of persistence and forecasting future values of state debt in the short term using time series analysis, i.e., an ARIMA model. The study covers the time series of Ukraine’s state debt data for the period from December 2004 to November 2020. A visual analysis of the dynamics of state debt led to the conclusion about the unstable debt situation in Ukraine and a significant increase in debt over the past six years. Using the Hurst exponent, the paper provides the calculated value of the level of persistence in time series data. Based on the obtained indicator, a conclusion was made on the confirmation of expediency to use autoregressive models for predicting future dynamics of Ukraine’s state debt. Using the EViews software, the procedure for forecasting Ukraine’s state debt by utilizing the ARIMA model was illustrated, i.e., the series was tested for stationarity, the time series of monthly state debt data were converted to stationary, the model parameters were determined and, as a result, the most optimal specification of the ARIMA model was selected.

This paper explores market efficiency in the Ukrainian stock market to determine whether there are differences between traditional and ESG indices. Different data properties related to market efficiency are explored: persistence (R/S analysis is used for these purposes), stationarity (ADF tests), normality (Kolmogorov-Smirnoff, Anderson-Darling test, etc.), resistance to market anomalies (Day of the week effect, abnormal returns and patterns they generate are tested using parametrical and non-parametrical statistical tests), etc. Database includes daily data from 2 conventional Ukrainian stock market indices (UX and PFTS) and ESG index (WIG Ukraine) over the period 2015–2022. The following hypothesis is tested in this paper: ESG indices are more efficient than traditional ones. The findings suggest that there are no significant differences between traditional and ESG indices: they have the same persistence, stationarity, do not fit normal distribution and are not influenced by explored market anomalies. So, despite the fact that companies listed in the ESG index are more transparent and thus characterized by lower information asymmetry, they are more liquid and popular among investors, ESG index is not more efficient than traditional ones. This might be the result of unfair practices called “washing” aimed at signaling the active ESG involvement with actual absence of it. This means that many ESG companies are actually traditional. To prevent such practices, the ESG reporting regulation needs to be revised.

Acknowledgment
Alex Plastun gratefully acknowledges financial support from the Ministry of Education and Science of Ukraine (0121U100473).