Legal framework for exchange: Types of international agreement: The EU Directive on Administrative Cooperation in Tax: Taxes covered by the Directive
The EU Directive on Administrative Cooperation allows for exchange of information regarding “all taxes of any kind”, but specifically excludes VAT, customs duties, and excise duties covered by other EU legislation. Social security contributions (such as NICs in the UK) are also excluded.
Although these taxes are excluded when considering a request or otherwise making an initial exchange under the Directive, once held the information exchanged for allowed taxes can be used in the administration or enforcement of “taxes and duties of any kind”. See IEIM200200 for more on the concept of exchanging for one type of tax and then subsequently finding other uses.