Parallel to recent significant changes to international tax rules, the G20, OECD and the European Union have furthered administrative cooperation to fill enforcement gaps that made previous rules, and could make new rules, less effective. Within these new administrative mechanisms, improvement of Exchange of Information (EoI) is probably the leading policy. In this regard, new standards and reviewing processes of EoI upon request, the Common Reporting Standard for automatic EoI, and the extension of EoI to new fields such as rulings or Country-By-Country Reports, have significantly changed the panorama on information available to tax authorities. However, the impact of such rules may not be limited to the administrative procedure, but it could also progressively lead to a significant change in practical application of allocation of income rules, both at treaty and domestic level. This is due to the use of identification rules that point to the ultimate owner of income and assets and because of two reasons. First, the economic ownership and substance analysis policy underlying G20, OECD and EU tax policy projects, namely the BEPS Action Plan; and second, the import of identification rules from protocols on information on financial activity to prevent crimes such as terrorism or drug-trafficking. This last one makes an impact on EoI for tax matters as the rules do not match at all the purposes of the rules they are inserted in. While these rules were developed in the 90s aimed at identifying natural persons behind structures used for financing and supporting criminal activities, EoI for tax matters should provide the information to apply tax rules, that is to assess taxes according to their ability to pay as prescribed by the relevant law. It is true that EoI does not define per se allocation of income. But when tax authorities receive a person linked to an asset or income upon new EoI Standards, it will be tempting to automatically allocate such asset or income to he or she. Thus, defining natural persons behind entities or contracts may not help but distort application of taxes as it may lead tax authorities to attribute the income or asset to a different person from the one that applicable law allocates it. Moreover, as those rules refer to natural person with reference to certain percentage of participation in the shares, it may lead to an almost automatic disregard of narrowly-held entities. Doing so, allocation of income rules on domestic tax law and tax treaties could in practice change radically. Thus, this paper aims at analysing new EoI rules as refers to the identification of the holder of assets or income, and if they match the purpose they serve. To do so, in the first part we will analyse identification rules in EoI; in the second part, we will briefly analyse attribution of income rules in tax treaties and we will compare them and identify the gaps between both set of rules and the possible changes in the application of tax treaties they may lead to.