Judgment of the Court of Justice in the joined cases Jacob and Lassus.
1. Article 8 of Council Directive 90/434/EEC, Merger Directive, must be interpreted as meaning that it does not preclude legislation of a Member State pursuant to which the capital gain resulting from an exchange of securities falling within the scope of that directive is established when the transaction occurs, but is taxed in the year in which the event putting an end to the deferred taxation occurs: in this case, the transfer of the securities received in exchange.
2. Article 8 of the Directive 90/434 must be interpreted as meaning that it does not preclude legislation of a Member State that provides for the taxation of the capital gain relating to an exchange of securities, in a case where taxation of the gain has been deferred, upon a subsequent transfer of the securities received in exchange, even though that transfer does not fall within the fiscal competence of that Member State.
3. Article 49 TFEU must be interpreted as meaning that it precludes legislation of a Member State which, in a situation where the subsequent transfer of securities received in exchange does not fall within the fiscal competence of that Member State, provides for taxation of the capital gain that is subject to tax deferral upon that transfer without taking into account any capital loss occurring at that time, whereas account is taken of such a capital loss when the taxpayer holding the securities is resident for tax purposes in that Member State on the date of the transfer. It is for the Member States, in compliance with EU law and, in the present case, the freedom of establishment in particular, to provide detailed rules for offsetting and calculating that capital loss.