Assurance Reports

in Luxembourg for an Approved Statutory Auditor (“Réviseur d’Entreprises Agréé”)

Strategy ISAE 3000, ISAE 3402, ISO Certifications

Assurance Reports in Luxembourg for an Approved Statutory Auditor (“Réviseur d’Entreprises Agréé”)

In Luxembourg, approved statutory auditors (“réviseurs d’entreprises agréés”) may issue several types of assurance and attestation reports, particularly in the fields of financial reporting, internal controls, outsourcing, IT governance, sustainability, and regulatory compliance. These engagements are generally performed under international standards issued by the IAASB (International Auditing and Assurance Standards Board).

The most commonly encountered assurance reports include:

Statutory audit reports on annual or consolidated financial statements

Limited review reports

ISAE assurance reports

Internal control and outsourcing reports

ESG and sustainability assurance reports

Compliance and regulatory attestation reports

ISO-related certification support engagements

ISAE 3000

IAASB ISAE 3000 is the international standard applicable to assurance engagements other than audits or reviews of historical financial information. It provides a broad framework for non-financial assurance engagements.

In Luxembourg, ISAE 3000 reports are widely used for:

ESG and sustainability reporting

GDPR and data protection compliance

Cybersecurity and information security controls

SOC 2-type reporting

Regulatory compliance assessments

Non-financial KPIs and operational processes

An ISAE 3000 engagement may result in:

Type I report: assessment of the design and implementation of controls at a specific date
Type II report: assessment of the operational effectiveness of controls over a defined period

ISAE 3000 is particularly relevant for service providers, fintechs, cloud operators, fund administrators, and regulated entities seeking to demonstrate robust governance and control environments to clients, regulators, and investors.

The standard is also increasingly used for sustainability assurance engagements in connection with ESG and CSRD reporting obligations in Luxembourg.

ISAE 3402

ISAE 3402 specifically addresses assurance reports on controls at a service organization. It is mainly focused on controls relevant to financial reporting and outsourced services.

Typical Luxembourg use cases include:

Fund administration services

Payroll outsourcing

IT hosting and cloud services

Transfer agency operations

Managed service providers

Financial services outsourcing

The objective of an ISAE 3402 report is to provide comfort to user entities and their auditors regarding the effectiveness of the service organization’s internal control system.

Two report types exist:

Type I: evaluates the design of controls at a given point in time
Type II: evaluates both design and operating effectiveness over a testing period, usually 6 to 12 months

ISAE 3402 is often considered the international equivalent of SOC 1 reporting and is especially important for organizations whose services may impact clients’ financial statements.

ISO Certifications

ISO certifications are internationally recognized standards designed to ensure quality, security, efficiency, and compliance within organizations. They are issued by the International Organization for Standardization and are widely used in Luxembourg across financial services, IT, industry, and professional services.

The most common ISO certifications include:

ISO 27001 – Information Security Management

ISO 27001 is the leading standard for information security management systems (ISMS). It focuses on:

Data protection
Cybersecurity
Risk management
Access controls
Business continuity

It is particularly important for cloud providers, fintech companies, PSFs, and regulated financial institutions.

ISO 9001 – Quality Management

ISO 9001 establishes requirements for quality management systems (QMS). It aims to improve:

Operational efficiency
Customer satisfaction
Process standardization
Continuous improvement

ISO 22301 – Business Continuity Management

This standard focuses on business continuity and resilience. It helps organizations ensure continuity of critical operations during disruptions or crises.

ISO 14001 – Environmental Management

ISO 14001 relates to environmental management systems and supports organizations in improving environmental performance and sustainability practices.

Relationship Between ISO and ISAE Reports

ISO certifications and ISAE reports are complementary:

ISO certifications confirm compliance with a management standard through certification processes.
ISAE reports provide independent assurance over the effectiveness of controls and processes.

In practice, many Luxembourg organizations combine ISO 27001 certification with ISAE 3000 or ISAE 3402 reporting to provide stronger assurance to regulators, investors, and clients