One of the most pressing areas of research today is that referred to digital taxation and, in particular, to Digital Services Taxes (DSTs) and their interaction with the existing international tax frameworks. Based on the understanding that users’ data has economic value and that the extraction and monetization of such data by businesses justifies new taxing rights over such value for the jurisdictions where users are located, many jurisdictions have introduced DSTs as unilateral measures to address the challenges posed by digital business models. These taxes often emerge as a response to the limitations of traditional corporate tax rules based on physical presence, which struggle to capture the revenue generated by digital businesses in the markets where they operate and extract users’ data.

However, the unilateral and divergent implementation of DSTs raises critical questions about, first, their underlying policy rationale, true nature and design features and, second, about their compatibility with existing tax treaties and investment agreements. These concerns are particularly significant because DSTs may conflict with core principles such as non-discrimination, tax treaty obligations, and protections afforded to foreign investors under bilateral investment treaties. Consequently, there is ongoing debate surrounding the legal and economic implications of DSTs, with particular focus on how these taxes align with established treaty frameworks. Additionally, the potential for cross-border tax disputes over DSTs warrants further analysis, especially considering ongoing efforts to resolve such disputes through international mechanisms.

By examining the underlying policy rationale and nature of DSTs and addressing their most problematic design features and implications, this research explores whether it is possible to develop a fair and coordinated DST which countries could rely on to capture the value that digital businesses extract from users’ data and contributions.

In addition to DSTs, the research also explores other alternative measures to address the tax challenges raised by the digitalized economy in a fair, effective and convenient way.

Global mobility of individuals and workers has dramatically accelerated in the last few years. Only a decade ago, labour mobility interested only a fraction of individuals, such as frontier and posting workers or international managers. However, technological advancements, propelled by the COVID-19 pandemic between 2020 and 2022, have prompted a swift adoption of new labour patterns. The remote exercise of labour activities has gone from being exceptional to becoming a common practice, rendering geographical proximity between the employee and the workplace largely immaterial. Concepts such as remote work, home office, work from anywhere, and digital nomads have emerged, disclosing new possibilities for a global labour supply. 

International tax rules have not yet been adjusted to such ongoing changes. Therefore, the application of traditional tax concepts, starting from the fundamental tenets of residence and source, these new realities raises numerous critical issues. Tax residence, permanent establishment, employment, and fixed base are all concepts under challenge and need to be revisited. International tax issues are further exacerbated by countries competing with one another for alluring desirable migrants, such as high-skilled workers or high-net-worth individuals (HNWIs), to relocate within their territory by offering them a series of tax benefits which are not ordinarily available to other categories of tax residents.

Against this background, this research line aims to analyse the challenges of the post-COVID-19 social and economic scenario to propose solutions updating the international tax system to the new reality of mobile individuals and remote work. It also considers equity concerns raised by the global mobility of individuals within and across countries.

Digital platforms are pivotal to our economy and society, redefining supply chains and how value is created. The role of these new digital intermediaries is of major importance in a wide range of activities, as marketplaces facilitating the supply of goods or services or hubs creating value through users’ interactions. The acquired prominence of  platforms in recent years has brought significant benefits, contributing to increased innovation, competitiveness, and welfare across the board. On the other hand, these new digital intermediaries raise a wealth of new policy and regulatory challenges, from competition safeguards to consumer and data protection.

The advent of digital  platforms has also put tax and VAT systems to the test. These digital middlemen have often been exploited by fraudsters to supply to customers in the European Union without declaring and charging VAT on their products, creating undue advantage against competitors and equity concerns. New rules for digital  platforms have been enacted in the European Union to cope with these issues. The new VAT in the Digital Age (ViDA) package, approved in 2025 but entering into force in 2028-2030, contains specific provisions for online platforms, which impose VAT collection obligations and provide clarification regarding the nature of platform services.

Against this background, this research line aims to analyse the challenges that the advent of online platforms brings in the field of VAT to propose solutions updating the current European VAT system. It also monitors the implementation of the new ViDA package and the VAT issues that the new rules have not (fully) addressed.

4.1. Substantive Direct Taxation

The taxation of digital assets, including non-fungible tokens (NFTs), presents significant challenges regarding the appropriate tax characterization and the identification of taxable events. As digital assets gain momentum, their decentralized and pseudonymous nature - enabled by blockchain technology - complicates the application of traditional tax principles, such as source-based and residence-based taxation.

A central question in this area of research is whether existing tax categories - such as capital gains, business profits, royalties, or income - adequately capture the economic substance of transactions involving NFTs and other blockchain-based assets. This study will explore whether these categories can accurately reflect the underlying economic activities and outcomes associated with the creation, sale, and transfer of NFTs. Additionally, the research will examine critical issues related to the valuation and liquidity of digital assets. Given the volatility and speculative nature of digital markets, determining the value of digital assets proves particularly challenging. The lack of standardized valuation methods for these assets further compounds these difficulties.

By addressing these issues, the research aims to contribute to the development of tax frameworks that better accommodate the unique characteristics of digital assets while ensuring tax compliance is both practical and enforceable in this rapidly evolving landscape.

4.2. VAT Characterization of Crypto Assets

The VAT treatment of crypto-assets has been the subject of Hedqvist (C-264/14), decided in October 2015. In that case, the CJEU ruled that transactions including the exchange of fiat currency for virtual currencies and vice versa performed for consideration are a taxable service, although exempt from VAT.

However, the VAT treatment of crypto-assets is far from clear. In Hedqvist (C-264/14), the CJEU referred to the VAT treatment of Bitcoin only. The Court’s findings were based on the assumption that Bitcoin has no other purpose than to be a means of payment accepted as such. This conclusion can hardly apply to the exchange of all the other crypto-assets currently available.

Moreover, the focus in Hedqvist (C-264/14) was limited to transactions concerning the exchange of Bitcoin for fiat currencies. However, other activities can be carried out in relation to crypto-assets, such as the exchange of non-fungible tokens (NFTs), digital wallet services, mining, proof-of-stake validation, or sales of virtual land.

Monitoring and localising transactions involving crypto-assets has also proven difficult in the context of a decentralised finance (DeFi) sector and a cross-border scenario. This uncertainty is also exacerbated by the lack of a harmonised legal framework for these instruments and activities at the international and European levels.

Against this background, this research line aims to analyse the current state of play of crypto-assets and related services to propose solutions and develop a common framework. It also considers comparative experience in other VAT systems, offering guidance to developing best practices on the VAT treatment of crypto-assets.

This research aims to explore the intersection of tax law and Generative AI, focusing on how AI-driven value creation, algorithms, and data should be taxed in the digital economy. Moving beyond traditional concerns about tax administration’s use of AI and legal safeguards like explainability and taxpayer rights, this research line will examine the substantive tax treatment of AI-tools and algorithms as key economic actors of future digital value chains. A core question of this research will be how tax frameworks should adapt to the fact that GenAI models generate economic value autonomously, raising novel issues of income attribution, transfer pricing, and corporate tax liability.

Additionally, the project will investigate the feasibility of embedding tax compliance mechanisms directly within AI and algorithmic systems. This includes designing AI models that incorporate real-time tax compliance, assessing whether AI-driven transactions could lead to compliance-by-design outcomes and analysing the potential for smart contracts and blockchain-based tax enforcement. By integrating insights from law, fiscal economics, and technology, this research will contribute to a forward-looking tax policy that accounts for the rapid evolution of AI-driven economies.