Flat Tax as an Instrument of Legal and Fiscal Competitiveness within the European Context

European taxation can no longer be regarded as a merely technical domain of public finance. It has progressively evolved into an instrument of economic power through which States compete for capital, entrepreneurs, family offices and highly specialised human expertise. In an economic environment where the mobility of wealth has become structural rather than exceptional, the decisive issue is not confined to the nominal level of taxation. What increasingly matters is the overall quality of the legal and economic ecosystem constructed around capital itself.

Traditional conceptions of fiscal sovereignty, historically tied to relatively stable territorial boundaries, are now confronted by a condition of permanent regulatory competition. Major international taxpayers increasingly choose jurisdictions, tax residences and corporate structures according to criteria resembling those governing the allocation of strategic investments. London, Dubai, Milan, Lugano, Monaco and Singapore compete not merely on financial or reputational grounds but on their capacity to guarantee stability, predictability and systemic efficiency over time.

Against this background, the Italian flat tax regime should be understood for what it substantively represents: not simply a fiscal measure but an operation of economic positioning. Its purpose extends beyond the immediate objective of increasing revenue or encouraging the relocation of affluent taxpayers. More fundamentally, the regime seeks to attract centres of decision making, international wealth and financial relationships capable of generating value that transcends the strictly fiscal sphere. The underlying question concerns Italy’s place within the European geography of private wealth and globally mobile capital.

For this reason, the flat tax cannot adequately be analysed solely as an instrument of tax policy. It must also be examined as a mechanism of regulatory competition between legal systems, particularly within a European context characterised by increasing mobility of both capital and high net worth taxpayers.

The experience of Central and Eastern European States illustrates how single rate tax systems have progressively been employed as instruments of economic attraction, administrative simplification and reinforcement of tax compliance. Estonia, Latvia and Lithuania inaugurated during the 1990s an initial phase of reforms based upon moderately elevated flat tax regimes. Romania, Bulgaria and Hungary later followed with considerably lower rates, frequently below the previous minimum thresholds applicable under progressive systems. The economic rationale underlying such reforms was relatively clear: reducing fiscal distortions, increasing transparency and rendering national tax systems more competitive within the post transition European framework.

Empirical evidence nevertheless reveals a more nuanced reality than the theoretical simplicity often associated with proportional taxation. In Russia, the 2001 reform coincided with a substantial increase in tax revenues and an improvement in compliance levels. Yet a significant body of scholarship observed that these outcomes could not automatically be attributed exclusively to the introduction of a single rate structure. The simultaneous strengthening of enforcement mechanisms and tax administration appears to have played an equally decisive role. Slovakia, by contrast, experienced more limited results. There, the flat tax exposed structural weaknesses connected with administrative inefficiency and persistently high labour related contributions, producing less favourable effects in terms of both revenue generation and voluntary compliance.

What emerges with some clarity is that no tax system can realistically be assessed through nominal rates alone. Even formally proportional regimes incorporate implicit forms of progressivity through deductions, allowances, tax credits and broader tax expenditures. The fiscal architecture of the systems examined demonstrates that adoption of the flat tax was almost invariably accompanied by compensatory mechanisms intended to mitigate regressive effects, particularly in relation to middle and lower income groups and economically vulnerable households. In substantive terms, this confirms that the distinction between progressive and proportional taxation is considerably less rigid than theoretical models often imply.

From a constitutional perspective, Article 53 of the Italian Constitution assumes central significance, requiring that the tax system be informed by principles of contributory capacity and progressivity. The Constitutional Court has consistently clarified that the constitutional principle does not require every individual tax to possess a progressive structure. Rather, progressivity must characterise the tax system considered as a whole. It therefore operates as a systemic organising criterion rather than an absolute constraint applicable to each isolated fiscal provision. The Court has also recognised that certain taxes are not technically suited to direct application of progressive criteria, particularly where no immediate connection exists with the taxpayer’s personal income.

The constitutional compatibility of the flat tax cannot therefore be evaluated in abstract terms. Its legitimacy depends upon the overall equilibrium of the fiscal system within which it operates. A proportional tax may remain entirely compatible with Article 53 where inserted into a broader framework capable of ensuring adequate redistributive effects through alternative fiscal and social instruments. Conversely, a mere reduction of taxation upon higher incomes coupled with contraction of the State’s redistributive capacity would risk undermining the principle of economic solidarity permeating the constitutional structure as a whole.

Comparative European analysis confirms the persistence of tension between fiscal competitiveness and redistributive imperatives. In several OECD countries of Western Europe strongly progressive systems remain in place with marginal rates exceeding fifty per cent in jurisdictions such as Denmark, France and Austria. Numerous Eastern European systems by contrast continue to maintain significantly lower rates within frameworks openly oriented towards attracting investment, businesses and internationally mobile taxpayers. These approaches ultimately reflect profoundly different conceptions of the relationship between State, market and redistribution of wealth.

Within this context, the simulations developed through EUROMOD and QUEST assume particular importance. They indicate that the introduction of progressive elements into flat tax systems may generate positive redistributive effects and reduce inequality indices without producing substantial macroeconomic contraction. Fiscally neutral reforms, especially where accompanied by labour tax credits or targeted allowances, appear capable of improving income distribution while simultaneously preserving employment, growth and fiscal sustainability. Perhaps the most sophisticated finding concerns the relatively limited adverse effects upon highly skilled labour supply coupled with stronger employment incentives for middle and lower income groups.

The contemporary debate surrounding the flat tax therefore no longer revolves simply around the ideological opposition between proportional and progressive taxation. The deeper issue concerns the capacity of the State to construct a coherent, competitive and constitutionally balanced fiscal system capable of reconciling economic attractiveness, legal certainty, financial sustainability and protection of contributory capacity. In an increasingly integrated European environment, the quality of a tax system is measured less by the radicalism of its rates than by the sophistication of its overall fiscal architecture and its ability simultaneously to preserve economic efficiency and social cohesion.

The Italian experience assumes particular relevance precisely because it attempts to reconcile the constitutional framework established by Article 53 with a strategy directed towards attracting high net worth individuals and internationally mobile capital.

Within the broader framework of increasing fiscal competition between legal systems, the Italian legislator has progressively moved away from an exclusively static conception of contributory capacity. In its place there has emerged an approach more closely aligned with the international contestability of mobile tax bases. The mobility of substantial fortunes has altered the relationship between fiscal sovereignty and territorial taxation in profound ways, compelling States to confront not only domestic redistributive requirements but also the need to preserve economic attractiveness, financial stability and systemic competitiveness.

OECD analyses prepared in connection with the 2024 G20 discussions illustrate how the increasing concentration of global wealth has revived debate concerning the role of taxation in addressing inequality. Particular emphasis has been placed upon the fact that individuals situated at the upper end of wealth distribution frequently benefit from lower effective rates than taxpayers deriving income primarily from labour. This occurs because of the qualitative composition of their income sources, the international fragmentation of investments and the availability of preferential regimes or sophisticated cross border planning structures. The result is a growing tension between substantive fairness and international fiscal competition.

It is precisely within this environment that the regime established under Article 24 bis of the TUIR was introduced with an explicitly attractive function. The regime permits individuals transferring their tax residence to Italy after remaining non resident for at least nine of the previous ten fiscal years to subject foreign source income to a lump sum substitute tax. Under the original structure the annual payment amounted to EUR 100,000 extendable by an additional EUR 25,000 for each family member joining the regime with a maximum duration of fifteen years.

The architecture of the regime reflects a particularly sophisticated exercise in tax engineering. The legislator did not introduce a general derogation from constitutional progressivity. Instead the preferential treatment remains confined to foreign source income while ordinary IRPEF taxation continues fully to apply to income generated within Italian territory. Constitutional progressivity therefore retains its role as the organising principle of the domestic fiscal system whereas substitute taxation is justified through a logic of wealth attraction which absent the regime would likely remain allocated to competing jurisdictions.

Viewed from this perspective, the Italian model constitutes one of the most advanced European examples of selective competitive taxation. Its objective is not limited to increasing direct revenue generated through the substitute levy itself. More importantly it seeks to attract investments, consumption, financial wealth and economic relationships characterised by elevated levels of human and relational capital. The highly capitalised taxpayer is thus regarded not merely as a subject of taxation but as a factor of economic attraction capable of generating broader indirect taxable bases.

The amendment introduced by Decree Law No. 113 of 2024 confirms this strategic orientation. The increase of the substitute tax from EUR 100,000 to EUR 200,000 for individuals transferring tax residence to Italy after 10 August 2024 does not alter the underlying nature of the regime. It does however recalibrate its political and constitutional equilibrium. The measure appears intended to reinforce the systemic sustainability of the regime by mitigating concerns connected with excessive compression of the principle of contributory capacity while nevertheless preserving the international competitiveness of the Italian legal order.

Substantively, the legislator has pursued a form of compensated progressivity. The redistributive sacrifice deriving from favourable taxation of foreign source income is counterbalanced by the expectation of positive indirect economic effects: newly localised taxable wealth, increased domestic consumption, expansion of related entrepreneurial and financial activities and strengthening of the national economic ecosystem. What emerges is an evolutionary conception of taxation in which contributory capacity is interpreted not solely in static patrimonial terms but also dynamically through the creation of economic value for the national system.

At the same time, international transparency standards promoted by the OECD through the Common Reporting Standard and the Crypto Asset Reporting Framework have progressively reduced the space historically available for traditional international tax evasion. Within this transformed environment, competition between legal systems increasingly shifts away from fiscal opacity and towards regulatory quality, legal certainty and institutional stability. Through the regime for new residents Italy has sought to position itself precisely within this new geography of global taxation.

Consequently, the relationship between constitutional progressivity and preferential regimes cannot be interpreted through rigidly antagonistic categories. Article 53 does not impose an absolute model of fiscal egalitarianism. Rather it requires that the tax system maintain overall coherence with the principles of contributory capacity, reasonableness and economic solidarity. From this perspective, the regime for new residents represents an attempt to synthesise domestic redistributive requirements with the demands of international competitive positioning illustrating how contemporary fiscal sovereignty is increasingly shaped less by nominal rates than by the strategic quality of the overall fiscal architecture.

To understand fully the significance of the Italian model it becomes necessary to compare it with other systems that have constructed part of their economic attractiveness around preferential tax regimes aimed at highly capitalised individuals.

Over recent years international taxation has undergone profound transformation. The multilateral automatic exchange of banking information operational since 2017 and progressively extended to more than one hundred jurisdictions has substantially reduced the scope for traditional offshore tax evasion. Simultaneously the agreement concerning a global minimum tax for multinational corporations has represented the most ambitious attempt to contain aggressive fiscal competition between States. Yet as emphasised by the EU Tax Observatory competitive pressure has by no means disappeared. Rather it has migrated towards more sophisticated forms frequently situated at the intersection of lawful tax planning, fiscal arbitrage and the personal mobility of large fortunes.

Within this framework special regimes for individuals possessing substantial wealth assume a strategic function of growing importance. They are no longer peripheral instruments but mechanisms of international positioning through which legal systems seek to attract mobile taxpayers, financial capital, qualified consumption and networks characterised by elevated economic value. The central issue is therefore institutional as much as fiscal: determining the extent to which a State may differentiate the treatment of new residents without undermining systemic coherence, perceptions of fairness or the broader political sustainability of taxation.

The Swiss case remains one of the historically most significant examples. Lump sum taxation permits certain foreign nationals who do not carry out gainful activity in Switzerland to be taxed according to their standard of living rather than ordinary income and wealth criteria. The regime retains a markedly selective character directed towards individuals possessing substantial economic resources and conditioned upon residence absent domestic professional activity. Its evolution nonetheless demonstrates that fiscal attractiveness cannot remain detached from democratic legitimacy. The abolition of the regime in several cantons beginning with Zurich together with subsequent tightening of federal rules suggests that preferential regimes if they are to endure must preserve at least a minimum threshold of social acceptability.

The United Kingdom offers a rather different trajectory. The reform of the non domiciled individuals regime effective from 6 April 2025 progressively abandons the traditional domicile based approach and replaces it with a residence based model. The new framework introduces a four year regime for new residents granting exemption on foreign income and capital gains to individuals who have not been tax resident in the United Kingdom during the preceding ten years. The British approach signals a broader paradigm shift: no longer an indefinitely renewable privilege but a temporally limited incentive intended to attract investment and human capital without permitting permanent separation between economic presence and ordinary fiscal contribution.

Portugal for its part has abandoned the former non habitual residents regime long regarded as one of the most effective instruments for attracting professionals, pensioners and internationally mobile individuals particularly through the preferential twenty per cent rate applicable to certain high value added activities. Its replacement by the IFICI regime centred upon scientific research and innovation reveals a more selective strategy. The objective is no longer the broad attraction of foreign taxpayers as such but the targeted recruitment of researchers, technology professionals and highly qualified individuals operating within strategically relevant sectors. The fiscal incentive remains though now subordinated to a more explicit industrial and economic policy rationale.

Compared with these models Italy occupies an intermediate yet distinctly sophisticated position. Article 24 bis of the TUIR neither adopts the Swiss expenditure based criterion nor replicates the former British domicile model nor confines itself exclusively to attraction of qualified human capital as under the contemporary Portuguese framework. Instead it establishes a substitute taxation regime applicable to foreign source income for individuals transferring tax residence to Italy following a substantial period of non residence while preserving ordinary progressive taxation on Italian source income.

Its most distinctive characteristic lies in the equilibrium it seeks to maintain between attractiveness and limitation. The highly capitalised taxpayer obtains predictability, certainty and long term fiscal stability with regard to foreign income. The Italian State in turn intercepts an economic base that would otherwise remain entirely external to the national system benefiting not only from the substitute tax itself but also from indirect effects upon consumption, real estate wealth, investment, professional services and the circulation of relational capital. The increase of the threshold from EUR 100,000 to EUR 200,000 for new entrants after 10 August 2024 further confirms the intention to render the regime politically more sustainable without depriving it of competitive effectiveness.

Comparative analysis therefore points towards a relatively clear conclusion. The age of fiscal opacity is progressively receding yet competition between legal systems remains very much alive. It has simply shifted towards transparent, codified, selective and legally defensible regimes. In this new environment the success of a tax system depends not solely upon the level of taxation but upon its capacity to guarantee legal certainty, institutional reputation, quality of life, regulatory stability and coherence with the fundamental principles of the legal order. It is on this terrain rather than through the simple promise of tax savings that the contemporary competition for global wealth is increasingly conducted. The success of such regimes has simultaneously rendered more visible the tension between allocative efficiency and redistributive justice, a question now situated at the centre of European fiscal debate.

The growing concentration of wealth within the highest segments of the population has reopened with renewed intensity the issue of taxation of high net worth individuals and particularly ultra high net worth individuals. The political and legal reality underlying this debate has become increasingly difficult to ignore. While systems of personal taxation remain formally progressive in relation to employment income, large fortunes frequently succeed in bearing lower effective burdens owing to the prevalence of capital income, undistributed profits, deferred capital gains, interposed corporate structures and sophisticated international wealth planning instruments.

European historical experience nevertheless counsels caution. Traditional net wealth taxes widespread across numerous legal systems between the post war period and the end of the twentieth century generated relatively modest revenues and were gradually abolished not primarily because large fortunes fled en masse but because the taxes themselves were technically defective. Thresholds were frequently set too low, taxable bases remained excessively narrow and numerous exemptions including those relating to corporate shareholdings, family businesses and illiquid assets progressively hollowed out the structure of the tax. The consequence was paradoxical: ordinary forms of wealth often bore the burden while the most substantial concentrations of capital frequently escaped effective taxation.

From this emerges a first fundamental lesson. Any contemporary form of wealth taxation cannot simply reproduce twentieth century models. If the objective is genuinely to address effective regressivity at the upper end of wealth distribution taxation must operate upon a broad base substantially free from structural exemptions and combined with very high thresholds capable of targeting only extreme wealth while avoiding distortive effects upon housing, pension savings, small enterprises and illiquid family assets.

It is within this perspective that the proposal discussed within the G20 concerning a global minimum tax on ultra high net worth individuals equal to two per cent of net wealth should be situated. The defining characteristic of the proposal does not consist in creating a wholly autonomous wealth tax. Rather it envisages a top up mechanism: where the taxpayer has already borne an adequate effective burden through taxes on income, capital gains, inheritances or comparable levies no additional amount would become payable otherwise an integration mechanism would apply up to the minimum threshold. The model appears considerably more surgical, less ideological and from a legal perspective more defensible.

Its significance lies in the attempt to target the gap between actual economic wealth and fiscally declared income. For extremely large fortunes contributory capacity does not necessarily manifest itself through taxable income flows. It may instead emerge through accumulated wealth, control of corporate assets, unrealised appreciation and the ability to finance consumption through leverage without generating taxable income. Limiting analysis exclusively to income taxation therefore risks accepting only a partial representation of real economic power.

At European level the debate assumes increasing institutional importance. Spain currently remains the only Member State maintaining a general net wealth tax accompanied by a solidarity tax on large fortunes. At the same time the European Parliament, the European Commission, the OECD, the International Monetary Fund and the United Nations have progressively reopened discussion concerning more selective and coordinated instruments of wealth taxation. Financial pressures associated with defence expenditure, climate transition, healthcare, infrastructure and public debt render the issue no longer merely academic but strategically unavoidable.

Enforcement remains decisive. Historical wealth taxes operated within comparatively opaque financial environments. Today however automatic exchange of information, beneficial ownership registers, administrative cooperation and transparency standards concerning financial and digital assets render implementation of taxation upon large fortunes significantly more credible than in the past. Such instruments may ultimately require reinforcement through anti expatriation mechanisms, effective exit taxes and trailing residence rules capable of neutralising purely opportunistic transfers of residence.

The broader conclusion appears difficult to escape. Taxation of extreme wealth cannot be conceived as a symbolic gesture or as a punitive instrument directed against capital itself. It must instead be designed as a selective, coherent and internationally sustainable legal infrastructure. Its function is not to penalise wealth creation but to correct a systemic fracture within the fiscal order: when those possessing the greatest economic capacity succeed in bearing the lowest effective burden the tax system progressively loses rationality, credibility and ultimately constitutional legitimacy.

The flat tax and comparable regimes thus reflect a wider transformation in the nature of contemporary fiscal sovereignty itself namely the transition from taxation as the exclusive expression of redistributive authority to taxation as a strategic infrastructure of international competitiveness.