Inna Tiutiunyk

A significant size of the shadow economy is a threat to the sustainable functioning of a country’s economy, its ability to finance economic and social programs. The paper studies the influence of the shadow economy on the macro-financial stability of the EU countries. The dependence between macro-financial stability and the size of the shadow economy was estimated using the quadrocentric (considering the four channels of the shadow economy) recursive (takes into account direct and inverse relationships between them) model. Dependence between indicators was analyzed using Euler’s methods, Calvo’s and Dixit Stiglitz’s principles, Taylor’s and Smets-Wouters’ function. It has been proved that shadow economy channels affect the macro-financial stability almost equally (an increase in the size of the shadow economy in Slovenia by 1% leads to a decrease in macro-financial stability by 0.562% for tax, 0.56% for investment, 0.572 for institutional, and 0.444 for social channels). At the same time, the growth in the volume of shadow transactions through one channel forms an impetus for the increasing intensity of use of the remaining channels to hide income. With the help of the payment matrix, the optimal level of drivers of shadow economy by which the targeted value of the level of macro-financial stability is achieved was determined. It was concluded that ensuring good governance in the direction of preventing shadow schemes of capital withdrawal should be carried out in terms of institutional, tax, social, and investment channels of the shadow economy.

Acknowledgment
This work was supported by the Slovak Research and Development Agency under the contract No. APVV-16-0602.

Tax competitiveness of the country characterizes the ability of the tax system to obtain permanent competitive advantages in attracting external and mobilizing internal financial resources due to the establishment of the optimal level of tax burden and differentiation of fiscal instruments. The complexity of this indicator determines the presence of a number of drivers of its formation. Shadow tax evasion is one of them. The purpose of the study is to assess the impact of the shadow tax evasion of taxpayers on the level of competitiveness of the tax system on the example of 11 European countries from 2011 to 2021. The methodological tools are regression analysis methods, Shapiro-Wilk tests, and Spearman’s rank correlation. It was determined that informal employment, informal production, and unregistered or informal entrepreneurship are the most common methods of tax evasion. Based on the results of the calculations, regression equations of the influence of shadow tax evasion on the level of competitiveness of the country’s tax system were constructed. It has been proven that shadow tax evasion exerts the greatest influence on the level of tax competitiveness of Slovenia (0.32), Romania (0.34), and Croatia (0.26). The least sensitive to shadow tax evasion is the competitiveness of the Czech Republic’s tax system (0.096). For most analyzed countries, this influence is carried out with a time lag of 2 years. Only in Croatia, this influence is the most substantial with a one-year lag.

Acknowledgment
The study is funded by the EU NextGenerationEU through the Recovery and Resilience Plan for Slovakia under the project No. 09I03-03-V01-00042.
The authors are grateful to the participants of projects “National security of Ukraine through the prevention of financial fraud and money laundering: war and post-war challenges” (2023–2025, state registration number: 0123U101945) and “De-shadowing and regulatory efficiency of environmental taxation: optimization modelling to ensure national security and rational use of nature” (2022–2024, registration number 0122U000777) for numerous discussions and comments.

In the conditions of permanent capital outflow and business registration by residents in other jurisdictions, the issue of developing a country’s marketing strategies for doing business and identifying the most effective mechanisms for increasing international tax attractiveness is urgent. The prerequisite of these processes should be the determination of the level of international tax competitiveness followed by identifying the most significant factors of its growth. The purpose of the study is to assess the level of international tax competitiveness as an element of marketing strategies of Ukraine and some EU countries during 2011–2021. The methodological tools are correlation-regression analysis, the Fisher method, and the multiplicative convolution method. The paper assessed the level of international tax competitiveness as a comprehensive indicator that considers procedural, institutional, moral-ethical, and economic components. The calculations showed that the most competitive are the tax systems of Estonia, Latvia, Lithuania, Croatia, Finland, the Czech Republic, and Hungary. Based on hierarchical and non-hierarchical (k-means method) clustering, 3 clusters of regions were identified. For each of them, based on an analysis of the features of the tax system construction and the comparison of marginal and average values, the criteria for the identification of competing countries and those with common development trends were formed. This makes it possible to determine the most effective mechanisms for the implementation of marketing strategies reforming tax policy from the point of view of increasing its international tax attractiveness.

Acknowledgment
The study is funded by the EU NextGenerationEU through the Recovery and Resilience Plan for Slovakia under the project No. 09I03-03-V01-00042.
The authors are grateful to the participants of projects “National security of Ukraine through the prevention of financial fraud and money laundering: war and post-war challenges” (2023–2025, state registration number: 0123U101945) and “De-shadowing and regulatory efficiency of environmental taxation: optimization modelling to ensure national security and rational use of nature” (2022–2024, registration number 0122U000777) for numerous discussions and comments.

The formation of the country’s tax competitiveness and countering the shadowing of the economy depend on several factors. One of them is an effective public administration. It defines state policy vectors, institutions’ critical tasks, and business and society development priorities. The aim of the paper is to analyze the impact of good governance on the country’s tax competitiveness and the level of the shadow economy of 11 EU countries and Ukraine in 2011–2021. The study employs statistical analysis of data series. It constructs a correlation field of points of relationship between indicators (to determine the general trends of changes in the level of the shadow economy, tax competitiveness, and the Good Governance Index). Linear mathematical model and Fishburn formula are used to construct an integral indicator of the level of efficiency of public management (Good Governance Index). Structural modeling methods formalize the influence of government management on the level of the shadow economy and tax competitiveness. It was found that the Government Efficiency Index and the Corruption Control Index exert the most significant correlation with the level of tax competitiveness and the shadow economy. Its increase of 1% leads to a rise in the level of tax competitiveness of Slovakia by 7.015%, Croatia by 6.889%, the Czech Republic by 6.606%, and Romania by 5.773%. At the same time, the smallest correlation with the level of tax competitiveness performs an Index of Political Stability and Absence of Violence/Terrorism.

Acknowledgment
The study is funded by the project VEGA – 1/0392/23 “Changes in the approach to the creation of companies’ distribution management concepts influenced by the effects of social and economic crises caused by the global pandemic and increased security risks.”
The authors are grateful to the participants of projects 0123U101945 and 0122U000777 for numerous discussions and comments.

Type of the article: Research Article

Abstract
Military and economic turbulence transform the relationships between factors shaping national cyber resilience. This study aims to analyze the impact of technological, institutional, and financial determinants on cyber resilience under armed conflict and post-conflict recovery. The empirical analysis covers neighboring European non-EU countries within the European security space that are exposed to armed conflict or post-conflict instability (Ukraine, Moldova, Georgia, Armenia, Azerbaijan, and Serbia) from 2010 to 2024, using panel data from the World Bank, IMF, and ENISA. Cyber resilience is measured by the Global Cybersecurity Index. Institutional, technological, and financial factors are proxied by standard governance, digitalization, and the financial sector and estimated using a fixed-effects model with Driscoll-Kraay robust standard errors. The results reveal pronounced regime-dependent effects. Institutional capacity plays a decisive role during armed conflict: government effectiveness shows a strong positive association with cyber resilience (β ≈ 1.04) but becomes statistically insignificant in post-conflict and stable environments. Technological factors exhibit context-sensitive effects: digital government development is positively associated with cyber resilience during armed conflict (β ≈ 0.95) and relative stability (β ≈ 1.78), while its impact weakens in post-conflict recovery. Macroeconomic conditions exert systematic influences across regimes: higher unemployment reduces cyber resilience (β ≈ −0.027), whereas inflation shows a positive association (β ≈ 0.008). Financial indicators display mixed and predominantly negative effects under relative stability. Accordingly, cybersecurity policy should be explicitly regime-sensitive: institutional and digital interventions should dominate during armed conflict, while governance and risk-management mechanisms should prevail in post-conflict and stable environments.

Acknowledgment
The authors acknowledge with gratitude the financial support provided by the Ministry of Education and Science of Ukraine for the research project “Modeling mechanisms for countering organized and transnational cybercrime in wartime and post-war times” (state registration number 0124U000550).

Type of the article: Research Article

Abstract
The growing importance of renewable energy in ensuring energy security and sustainable development has increased attention to the role of public finance, particularly at the regional level. This study aims to assess whether different categories of regional public expenditure are associated with renewable energy development in Ukraine, distinguishing between installed capacity and electricity generation. The analysis is based on a balanced panel dataset for 25 Ukrainian regions over 2018–2021 and applies two-way fixed effects models with lagged specifications and Driscoll–Kraay standard errors. The results show that expenditures on electric transport exhibit the strongest positive association with installed renewable energy capacity (β ≈ 0.078, p < 0.001), followed by SME support (β ≈ 0.025, p < 0.001), other environmental activities (β ≈ 0.017, p < 0.001), and natural resource management (β ≈ 0.013, p < 0.001). In contrast, most general economic expenditures are not statistically significant, suggesting that these expenditure categories are not statistically associated with higher renewable energy development within the analyzed period. For renewable electricity production, contributions to the statutory capital of enterprises are positively associated (β ≈ 0.006, p < 0.05), while co-financing of investment projects is negatively associated (β ≈ −0.027, p < 0.001), reflecting implementation lags. Additionally, capital investments in environmental protection are negatively associated with renewable electricity production (β ≈ −0.072, p < 0.001), suggesting that installed capacity expansion differs from renewable electricity production.

Acknowledgment
The authors acknowledge funding from the Swiss National Science Foundation (SNSF) [Grant No. IZURZ1_224119]. The authors bear sole responsibility for the conclusions and results of the research.