Luxembourg-San Marino MAP loses its three-year expiry

Taxpayers with Luxembourg–Saint-Marin cross-border positions who seek relief under the Convention between the Grand-Duché de Luxembourg and the République de Saint-Marin tendant à éviter les doubles impositions en matière d'impôts sur le revenu et sur la fortune, and the Protocole y relatif, no longer face an automatic end to the mutual agreement procedurePublic. Article 1 of the Avenant, fait à Luxembourg, le 14 mai 2025, deletes a single sentence in paragraph 2 of Article 25 (Procédure Amiable) of the ConventionPublic: "La procédure amiable expire à la fin de la troisième année suivant l'année dans laquelle le contribuable a présenté le cas."

The deletion removes the three-year expiry that previously cut off a case counted from the year in which the taxpayer presented it.Public A procedure opened under Article 25 therefore no longer lapses by operation of that sentence once the third year-end after presentation passes.Public The Avenant makes no other change to Article 25 and no change to the taxes, persons or relief conditions of the Convention itself, which was signed à Luxembourg, le 27 mars 2006, and previously amended by the Protocole signed à Rome, le 18 septembre 2009.

Entry into force followed the bilateral notification mechanism in Article 2 of the Avenant. Each Contracting State notifies the other in writing through the diplomatic channel once its applicable procedures are complete, and the Avenant enters into force on the date of the last of those notifications. The conditions were fulfilled on 16 September 2026Public, and the Avenant entered into force with respect to both Contracting Parties on that dayPublic, as recorded in the Journal officiel notice and consistent with Article 2, paragraphe 2.

Temporal application runs from the next calendar year. Article 2, paragraphe 2, provides that the provisions of the Avenant apply to tax years beginning on or after 1 January of the calendar year immediately following the year of entry into force.Public With entry into force in 2026, the amended Article 25 applies to tax years beginning on or after 1 January 2027.Public Cases concerning earlier tax years remain governed by the prior version of the provision.Public

Domestic approval on the Luxembourg side came through the loi du 10 mars 2026, published in the Journal officiel du Grand-Duché de Luxembourg, Mémorial A, N° 130 du 16 mars 2026, which approves the Avenant of 14 May 2025. The Avenant was concluded in two originals at Luxembourg on 14 May 2025 in French, Italian and English, all texts being equally authentic. For practitioners, the operational point is direct: a mutual agreement case under the Luxembourg–Saint-Marin Convention concerning a 2027 or later tax year cannot be treated as expired at the end of the third year after presentationPublic, and file management, follow-ups with the competent authorities and parallel domestic remedies should be organised on that basis.

Legal basis: the Avenant, fait à Luxembourg, le 14 mai 2025, Article 1 and Article 2, paragraphe 2, approved by the loi du 10 mars 2026 and entered into force on 16 September 2026Public.