Anita Radman Peša

This paper analyzes financial markets in four developing countries (Croatia, Serbia, Slovenia, Slovakia) using daily returns of their respective stock market indices from January 1, 2006 till December 31, 2016, timeframe which was rarely analyzed. Analysis was conducted by various statistical tests, more precisely serial correlation test, runs test, Augmented Dickey-Fuller test, unit root test, variance ratio test and test of January effect. Results suggest that all analyzed indices, except BelexLine (Serbia), confirm weak form of efficient market hypothesis, while the results on the index BelexLine are mixed and it can be concluded that it does not follow weak form of efficient market hypothesis. Given these results, it can be said that not only passive approach to portfolio management is more appropriate on all indices, except BelexLine, but also additional test and more complex models are necessary in order to confirm this conclusion.

Type of the article: Research Article

Abstract
This study develops DIGTAXEU, a conceptual model that elucidates the primary determinants of digital economy taxation in the EU and their interrelationships. The model identifies nine dimensions, including the definition of the digital economy, profit shifting, jurisdictional scope, taxation of multinational enterprises, revenue thresholds, fair taxation, international agreements, political and economic diversity among Member States, and unilateral tax measures. The DIGTAXEU model was developed using interviews with four experts representing key institutions in international and European Union tax policy, including the OECD, the European Commission, and the Permanent Representations of Austria and Hungary to the European Union. The findings demonstrate that digital taxation in the EU is driven by the interplay of cross-border digital business models, fragmented national tax responses, and incomplete international coordination. Consequently, DIGTAXEU provides a structured analytical framework for understanding regulatory fragmentation and informing the development of a more coherent and equitable EU digital tax architecture. The identified dimensions function in a mutually dependent manner, shaping the consistency and overall effectiveness of digital tax policy. At the same time, disparities among national tax measures, together with the absence of comprehensive international harmonization, continue to hinder the development of a unified digital taxation framework.

Acknowledgment
Funded by the European Union – NextGenerationEU: Incentives towards the optimization of digital tax policies and responsibilities in the EU (DIGTAXEU) IP-UNIZD 2025–2029. The views and opinions expressed are those of the authors only and do not necessarily reflect the official views of the European Union or the European Commission. Neither the European Union nor the European Commission can be held responsible for them.