Selected Publications

Network-based asset allocation strategies
by Tomas Výrost, Štefan Lyócsa and Eduard Baumöhl
in The North American Journal of Economics and Finance, 2019, vol. 47, pp. 516-536

In this study, we construct financial networks in which nodes are represented by assets and where edges are based on long-run correlations. We construct four networks (complete graph, a minimum spanning tree, a planar maximally filtered graph, and a threshold significance graph) and use three centrality measures (betweenness, eigenvalue centrality, and the expected force). To improve risk-return characteristics of well-known return maximization and risk minimization benchmark portfolios, we propose simple adjustments to portfolio selection strategies that utilize centralization measures from financial networks. From a sample of 45 assets (stock market indices, bond and money market instruments, commodities, and foreign exchange rates) and from data for 1999 to 2015, we show that irrespective of the network and centrality employed, the proposed network-based asset allocation strategies improve key portfolio return characteristics in an out-of-sample framework, most notably, risk and left-tail risk-adjusted returns. Resolving portfolio model selection uncertainties further improves risk-return characteristics. Improvements made to portfolio strategies based on risk minimization are also robust to transaction costs.

Quantile coherency networks of international stock markets
by Eduard Baumöhl together with Syed Jawad Hussain Shahzad
in Finance Research Letters, 2019, vol. 31, pp. 119-129

This paper uses the novel quantile coherency approach to examine the tail dependence network of 49 international stock markets in the frequency domain. We find that geographical proximity and state of market development are important factors in stock markets networks. Both the short- and long-run connectedness significantly increased after the global financial crisis and spillover is higher during bearish market states, highlighting the possibility of contagion effect mainly among developed markets. Frontier and emerging markets are relatively less connected. These findings have implications for international equity market diversification and risk management.

Central bank announcements and realized volatility of stock markets in G7 countries
by Štefan Lyócsa and Tomáš Plíhal together with Peter Molnár
in Journal of International Financial Markets, Institutions and Money, 2019, vol. 58, pp. 117-135

We investigate the impact of monetary policy announcements on stock market volatility in the U.S., Canada, Japan, the U.K., Germany, France and Italy during the 2006–2016 period. More specifically, we study the impact of policy rate and quantitative easing announcements of domestic and foreign central banks on realized volatility before, during, and after the event. We find that on the day of an interest rate announcement of the domestic central bank, volatility increases in a manner that is both statistically and economically significant. We also find a decline in volatility five days after an interest rate announcement across all countries in our sample. We further find that quantitative easing announcements have no impact on stock market volatility not only at but also five days before and five days after the announcement date.

Institutions and determinants of firm survival in European emerging markets
by Eduard Baumöhl together with Ichiro Iwasaki and Evžen Kočenda
in Journal of Corporate Finance, 2019, vol. 58, pp. 431-453

We analyze the impact of institutional quality on firm survival in 15 European emerging markets. We employ the Cox proportional hazards model with a large dataset of firms during 2006–2015. Our results show that institutional quality (IQ) is a significant preventive factor for firm survival, and it displays diminishing returns as its effect is largest for low-level IQ countries and smallest for high-level IQ countries. In terms of specific indicators, the level of national governance and the extent of corruption control exhibit the key impacts. In terms of firm-specific controls, indicators of ownership structure and aggregate financial performance are the economically most significant factors associated with increased survival probability of firms in European emerging markets.