The glossary to understand and take action

Fiduciary firm

A fiduciary firm is a service provider offering, depending on its organisation and authorisations, accounting, tax, administrative or corporate services.

Notion comptable, fiscale ou juridique · Luxembourg Fiduciaries Editorial Team · Reviewed on

Understand the scope

Definition and points to distinguish

This designation does not prove an authorisation covering all activities. The engagement letter and professional registrations specify the relevant scope for your file.

In your file

What this changes in practice

The term fiduciary firm covers different offerings: accounting, tax returns, payroll or administrative support. You should start with your needs and then check the skills and authorisations required for the intended engagement. The firm does not automatically take over all of the manager’s responsibilities. The quality of operations also depends on the provision of supporting documents, the allocation of approvals and the ability to recover data at the end of the relationship.

A scenario to help you understand

Educational example

A founder requests a proposal for their company. They distinguish start-up support, monthly bookkeeping, annual accounts and payroll in order to compare proposals covering the same scope rather than an ambiguous overall price.

Fictitious situation, presented to illustrate the concept.

Prepare for what comes next

Points to check

  • Lister les prestations attendues
  • Vérifier les statuts professionnels pertinents
  • Prévoir les livrables, accès et conditions de sortie

The practical question

Find out more

Que faut-il comparer entre deux offres de fiduciaire ?

Comparez le périmètre exact, les livrables, les échéances et les échanges inclus, pas seulement un prix mensuel. Précisez la tenue, les déclarations, la paie, les dépôts et les demandes de conseil. Vérifiez les frais supplémentaires et la restitution des données. Une offre moins chère peut simplement couvrir moins de travaux ou demander davantage de préparation interne.

Connecting concepts

Terms to know as well

Continue with the concepts, contacts and procedures related to this topic.

Chartered accountantThe chartered accountant practises a regulated profession, with assignments relating in particular to accounting and advisory services within the authorised framework.Engagement letterThe engagement letter formalises the services agreed between a professional and their client, together with the conditions for their performance.Reversibility of accounting dataReversibility refers to the ability to retrieve the documents and data needed to continue management with another tool or service provider.OECThe Ordre des experts-comptables (OEC) is Luxembourg's professional body for the chartered accountancy profession.Institut des réviseurs d’entreprises (IRE)The Institut des réviseurs d’entreprises (IRE) is the professional body for statutory auditors in Luxembourg.DomiciliationCompany domiciliation organises, in situations provided for by law, the establishment of a registered office with an authorised third party and the agreed services.

Put it into practice

Explore further with our guides

Practical guideWhat does a fiduciary firm do? Define the services and engagement letterPractical guideChoosing a fiduciary firm in Luxembourg: criteria and questions to ask

Sources and verification

References consulted on 20 September 2026. Official procedures specify the applicable conditions and exceptions.

This guide explains a general process. The applicable rules depend on your situation; it does not constitute personalised advice. Report a correction.

A definition gives you a reference point. To examine your situation, clarify your question with a professional.