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    A Causal Relationship Among the Financial Indicators of Bitcoin, Gold, and VIX: An Empirical Analysis of the Fragile Five
    (Istanbul Univ, 2023) Karatas, Emin; Karatas, Ayyuce Memis
    This research discusses the causal relationship among the exchange rates, 10-year bond yields, and Central Bank policy rates with regard to the countries known as the Fragile Five (F5) by comparing them to global indicators such as gold, Bitcoin price, and the Volatility Index (VIX). The study takes into consideration the bond yields, exchange rates, and interest rates of T & uuml;rkiye, India, Indonesia, South Africa and Brazil in terms of their causal relationship with one another. The study also identifies some causal relationships among gold, bitcoin, and VIX with each other as global indicators by using the Toda Yamamoto approach to the Granger causality test. This study has arrived at the conclusion that a causal relationship exists between exchange rates and interest rates for T & uuml;rkiye, Indonesia, and South Africa but not for Brazil or India. VIX is the most significant variable, as it is affected by seven different variables, including policy rates and different exchange rates. In addition, none of the variables are seen to Granger cause bitcoin's price.
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    Do impact of cash flows and working capital ratios on performance of listed firms during the crisis? The cases of EU-28 and Western European countries
    (Emerald Group Publishing Ltd, 2023) Akgun, Ali Ihsan; Karatas, Ayyuce Memis
    PurposeThis study examines investigating the relationship between cash flows, working capital ratios and firm performance during the global financial crisis.Design/methodology/approachTo examine the relationship between cash flow, working capital ratios and firm performance for EU-28 or Western European Countries (Norway, Turkey and Switzerland) listed firms, both panel and ordinary least squares (OLS) regression model are used to analyze the data obtained from sample.FindingsThe study empirical findings suggest that global financial crisis has negative effect on firm performance for all sample. In addition, our interaction term result shows that cash flows variables such as cash holding level (CHL) x Crisis, cash interactive effect (CIE) x Crisis and gross working capital ratio (GWC) x Crisis not contributed to firm performance for EU-28 listed firms. However, the authors find that net working capital ratio (NWC) x Crisis have statistically significant and positive effects on firm performance with return on assets (ROA).Practical implicationsThe findings of the study provide evidence for managers that listed firms have reduced working capital expenditures to increase cash holdings level during the financial crisis. The authors find that cash flow variables with CHL have positive effect on firm performance with return on equity (ROE) in Western European Countries and these results are consistent with Opler et al. (1999)'s empirical results, while CIE have a negative impact on firm performance such as ROE and earnings before interest tax margin (EBITM).Originality/valueGlobal financial crisis emphasizes the importance of working capital and liquidity that suggests an efficient cash holdings policy in response to the uncertainty following the crisis.
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    The nonlinear relationship between bitcoin mining and carbon emissions in the context of renewable energy
    (Emerald Group Publishing Ltd., 2023) Karatas, Ayyuce Memis; Karatas, Emin; Kapusuzoglu, Ayhan; Ceylan, Nildag Basak
    This chapter presents an overview of the Bitcoin and its impacts on the environment and economics from the viewpoint of carrying out a systematic analysis of the literature related to the environmental and economic effect of digital currency. It is aimed to summarize and critically examine the points of view regarding Bitcoin mining, considering its effects on global warming and the social environment, employing peer-reviewed data associated through literatures. As a result, this study provides the chance to analyze the set of knowledge regarding the effects of the Bitcoin mining procedure on the ecosystem in regard to energy use and CO2 emissions regarding unit root tests and causality test based on nonlinear models. The results show that there exists a nonlinear causal relationship between statistics on Bitcoin mining and the CO2 emissions. The results also imply that Bitcoin remains to be a tool utilized in the economic environment for a range of objectives despite high energy consumption and some negative environmental impact within the scope of renewable energy; hence, authorities would take Bitcoin mining impacts into account to reduce CO2 emissions. © Ayyuce Memis Karatas, Emin Karatas, Ayhan Kapusuzoglu and Nildag Basak Ceylan.