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Thomas Walther
Former Member
Title
Prof. Dr.
Last Name
Walther
First name
Thomas
Phone
+41 71 224 2088
Now showing
1 - 10 of 37
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PublicationEnvironmental Hazards and Risk Management in the Financial Sector: A Systematic Literature ReviewWe conduct a systematic literature review on environmental and climate‐related risk management in the financial sector. We classify the current literature into three categories: (i) the impact of environmental concerns on financial risk; (ii) the current state of environmental risk practices in the financial sector; and (iii) measures to assess the financial exposure to environmental risks. We find that financial institutions can reduce their risk exposure by highly committing with environmental responsibility and performance. Moreover, the increase in willingness to assess climate‐related financial risk incentivizes corporate managers to adopt more proactive environmental policies and practices.Type: journal articleJournal: Journal of Economic SurveysVolume: 35Issue: 2DOI: 10.1111/joes.12411
Scopus© Citations 35 -
PublicationModeling and Forecasting Commodity Market Volatility with Long-term Economic and Financial VariablesThis paper investigates the time-varying volatility patterns of some major commodities as well as the potential factors that drive their long-term volatility component. For this purpose, we make use of a recently proposed GARCH-MIDAS approach which typically allows us to examine the role of economic and financial variables of different frequencies. Using commodity futures for Crude Oil(WTI and Brent), Gold, Silver and Platinum as well as a commodity index, our results show the necessity of disentangling the short-term and long-term components in modeling and forecasting commodity volatility. They also indicate that the long-term volatility of most commodity futures is significantly driven by the level of the global real economic activity as well as the changes in consumer sentiment, industrial production, and economic policy uncertainty. However, the forecasting results are not alike across commodity futures as no single model fits all commodities.
Scopus© Citations 37 -
PublicationValue-at-Risk for South-East Asian Stock Markets: Stochastic Volatility vs. GARCHThis study compares the performance of several methods to calculate the Value-at-Risk of the six main ASEAN stock markets. We use filtered historical simulations, GARCH models, and stochastic volatility models. The out-of-sample performance is analyzed by various backtesting procedures. We find that simpler models fail to produce sufficient Value-at-Risk forecasts, which appears to stem from several econometric properties of the return distributions. With stochastic volatility models, we obtain better Value-at-Risk forecasts compared to GARCH. The quality varies over forecasting horizons and across markets. This indicates that, despite a regional proximity and homogeneity of the markets, index volatilities are driven by different factors.Type: journal articleJournal: Journal of risk and financial management : JRFMVolume: 11Issue: 2DOI: 10.3390/jrfm11020018
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PublicationBitcoin is not the New Gold - A Comparison of Volatility, Correlation, and Portfolio PerformanceCryptocurrencies such as Bitcoin are establishing themselves as an investment asset and are often named the New Gold. This study, however, shows that the two assets could barely be more different. Firstly, we analyze and compare conditional variance properties of Bitcoin and Gold as well as other assets and find differences in their structure. Secondly, we implement a BEKK-GARCH model to estimate time-varying conditional correlations. Gold plays an important role in financial markets with flight-to-quality in times of market distress. Our results show that Bitcoin behaves as the exact opposite and it positively correlates with downward markets. Lastly, we analyze the properties of Bitcoin as portfolio component and find no evidence for hedging capabilities. We conclude that Bitcoin and Gold feature fundamentally different properties as assets and linkages to equity markets. Our results hold for the broad cryptocurrency index CRIX. As of now, Bitcoin does not reflect any distinctive properties of Gold other than asymmetric response in variance.Type: journal articleJournal: International review of financial analysisVolume: 59
Scopus© Citations 504 -
PublicationType: journal articleJournal: WiSt - Wirtschaftswissenschaftliches StudiumVolume: 48Issue: 2-3
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PublicationType: journal articleJournal: Finance Research LettersVolume: 22C
Scopus© Citations 9 -
PublicationType: journal articleJournal: Wirtschaftswissenschaftliches Studium : WiStVolume: 46Issue: 1
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PublicationExpected Shortfall in the Presence of Asymmetry and Long Memory: An Application to Vietnamese Stock MarketsPurpose This study aims to analyse the conditional volatility of the Vietnam Index (Ho Chi Minh City) and the Hanoi Exchange Index (Hanoi) with a specific focus on their application to risk management tools such as Expected Shortfall (ES). Design/methodology/approach First, the author tests both indices for long memory in their returns and squared returns. Second, the author applies several generalised autoregressive conditional heteroskedasticity (GARCH) models to account for asymmetry and long memory effects in conditional volatility. Finally, the author back tests the GARCH models’ forecasts for Value-at-Risk (VaR) and ES. Findings The author does not find long memory in returns, but does find long memory in the squared returns. The results suggest differences in both indices for the asymmetric impact of negative and positive news on volatility and the persistence of shocks (long memory). Long memory models perform best when estimating risk measures for both series. Practical implications Short-time horizons to estimate the variance should be avoided. A combination of long memory GARCH models with skewed Student’s t-distribution is recommended to forecast VaR and ES. Originality/value Up to now, no analysis has examined asymmetry and long memory effects jointly. Moreover, studies on Vietnamese stock market volatility do not take ES into consideration. This study attempts to overcome this gap. The author contributes by offering more insight into the Vietnamese stock market properties and shows the necessity of considering ES in risk management. The findings of this study are important to domestic and foreign practitioners, particularly for risk management, as well as banks and researchers investigating international markets.Type: journal articleJournal: Pacific Accounting ReviewVolume: 29Issue: 2
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PublicationTrue or Spurious Long Memory in European Non-EMU CurrenciesWe examine the Croatian Kuna, the Czech Koruna, the Hungarian Forint, the Polish Złoty, the Romanian Leu, and the Swedish Krona whether their Euro exchange rates volatility exhibits true or spurious long memory. Recent research reveals long memory in foreign exchange rate volatility and we confirm this finding for these currency pairs by examining the long memory behavior of squared residuals by means of the V/S test. However, by using the ICSS approach we also find structural breaks in the unconditional variance. Literature suggests that structural breaks might lead to spurious long memory behavior. In a refined test strategy, we distinguish true from spurious long memory for the six exchange rates. Our findings suggest that Czech Koruna and Hungarian Forint only feature spurious long memory, while the rest of the series have both structural breaks and true long memory. Lastly, we demonstrate how to extend existing models to jointly model both properties yielding superior fit and better Value-at-Risk forecasts. The results of our work help to avoid misspecification and provide a better understanding of the properties of the foreign exchange rate volatility.Type: journal articleJournal: Research in international business and financeVolume: 40
Scopus© Citations 17 -
PublicationType: journal articleJournal: Energy EconomicsVolume: 58
Scopus© Citations 85