What GSL does

GSL is a Luxembourg-based fiduciaire founded in 2007 and headquartered in Esch-sur-Alzette, providing accounting, tax advisory, payroll/social secretariat, statutory and contractual audit, and corporate management services (commissioner, administrator, liquidator roles). The firm operates through three divisions: GSL Fiduciaire, GSL Révision, and GSL Management, and serves a diversified client base of medium-to-large companies, liberal professions (doctors, architects, lawyers), private individuals, and ASBL/non-profit organizations. Its service delivery is anchored on the Odoo ERP platform, supplemented by BOB50 and Fisc-in for accounting and tax preparation, with offerings that range from full delegated bookkeeping to client-managed daily operations backed by GSL's expert review.

GSL generates revenue through professional services fees billed annually on a quote-based, customized pricing model tied to scope, portfolio size, and complexity. There are three primary revenue streams: core fiduciaire services, audit/revision engagements, and corporate management mandates. Go-to-market is sales-led and relationship-driven, supported by educational content marketing (regular blog posts on Luxembourg tax and compliance topics) and community participation such as the annual RTL Steierdag Tax Day. The firm has no publicly disclosed revenue, no external investors, and no parent company; it is privately held under sole leadership of Associé-Gérant Luc Schmitt, who assumed the role on June 24, 2024. A strategic partnership with Odoo positions GSL as both an implementation partner and ongoing support provider for clients adopting the Odoo accounting application, representing a modest technology-enabled differentiation within an otherwise traditional professional services offering.

Name

GSL

Legal name

GSL Luxembourg

Website

https://gsl.lu

Company type

Private

Founded year

2007

Operating status

Operating

Headcount range

11–50 employees

Short description

GSL is a privately held Luxembourg fiduciaire founded in 2007, offering accounting, tax advisory, payroll, audit, and corporate management services to medium-to-large companies, liberal professions, individuals, and non-profits via its Odoo-enabled service platform.

Ownership category

akta.pro rank

Product category

Accounting and Audit Services

NAICS

Accounting, Tax Preparation, Bookkeeping, and Payroll Services (5412)

SIC

Services-Miscellaneous Business Services (7380), Services-Management Services (8741)

akta.pro primary industry

Indirect Tax (VAT/GST/Sales & Use) Services (BPAHABAJ)

akta.pro secondary industry

Payroll Tax Filing, Compliance & Remittance (BPACAIAC)

Keywords

• Luxembourg accounting services
• Statutory audit services
• Tax advisory
• Payroll administration
• Corporate domiciliation

Headquarters

HQ city

Esch-sur-alzette

HQ country

Luxembourg

HQ region

Europe

Offices1 record

Markets served

GTM type

B2B

Offering type

Services

Cost components

Personnel, Operations, Technology or R&D, Marketing or Sales, Infrastructure

Revenue model

1. Fiduciaire Services: Core accounting, tax advisory, and social secretariat services for businesses and individuals. Services include bookkeeping, tax planning, payroll management, and ongoing financial compliance support.
2. Audit/Revision Services: Statutory and contractual audit services for annual financial statements, including legal audit compliance and voluntary certification.
3. Management Services: Commissioner, administrator, and liquidator services for corporate governance and restructuring needs.

Pricing tiers

Go-to-market motion1 record

Distribution channels1 record

Marketing channels3 records

Core offering

GSL is a Luxembourg fiduciaire providing statutory accounting, statutory audit, tax advisory and tax filing, payroll administration, corporate domiciliation, and full corporate management services for medium and large companies, liberal professions, ASBLs/non-profits, and individual clients. Its audit team performs legal revision engagements, while its accounting and payroll teams deliver ongoing bookkeeping, VAT and corporate tax returns, social-security declarations and salary administration through partners such as Odoo, BOB50 and Fisc-in. The firm also offers company formation and ongoing secretarial/legal administration support for Luxembourg entities.

Product overview

GSL is a Luxembourg-based accounting and audit firm offering a unified service portfolio centered on three core offerings: Fiduciaire (accounting, tax advisory, and payroll services), Révision (statutory and contractual audit services), and Management (corporate oversight roles). The firm differentiates through Odoo-based accounting outsourcing, providing clients with real-time cloud access to financial data. Additional services include company formation support, ASBL/non-profit compliance, and specialized tax advisory for individuals and businesses navigating Luxembourg regulations.

Differentiator

Problem solved

Functional benefit

Products and services

• Fiduciaire (Accounting & Bookkeeping Services)

Quantifiable outcome

• 14.7% tax reduction for families earning €75,000 under 2025 reform
• +1 more outcomes

Named customers3 records

Segments4 records

Ideal customer profiles4 records

Technology focussed No

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

Integration1 record

Feature2 records

Partnerships

One partnership is on record.

• OdoocoreTechnology or Integration · 1 January 2024Strategic partnership where GSL Fiduciaire implements and supports Odoo's accounting application for clients. GSL provides setup, configuration, ongoing support, and technical assistance for Odoo accounting modules including invoice management, bank reconciliation, VAT declarations, and annual account preparation.

Scale indicators2 records

Recent moves5 records

Expansion highlights5 records

Broad incumbents

• Mazars Luxembourg: Mazars Luxembourg delivers audit, tax, and advisory services. Comparable as a similarly broad professional services competitor with statutory audit, tax compliance, and corporate advisory expertise.
• Grant Thornton Luxembourg: Grant Thornton Luxembourg provides audit, tax, accounting, and advisory services to mid-market clients. It directly overlaps with GSL's fiduciaire/audit/multi-line professional services model in the same Luxembourg market.
• Baker Tilly Luxembourg: Baker Tilly Luxembourg offers audit, accounting, tax, and advisory services with a strong SME and mid-market focus. It competes head-to-head with GSL on fiduciaire-style engagements and statutory audit work in Luxembourg.
• RSM Luxembourg: RSM Luxembourg provides audit, tax, accounting, and consulting services. Compares to GSL on service breadth and mid-market client focus across the same fiduciaire-adjacent engagements.
• BDO Luxembourg: BDO Luxembourg is a major mid-tier audit, tax, and advisory network active in Luxembourg. It is comparable to GSL as a similarly broad professional services competitor serving mid-market and SME clients across fiduciaire-style engagements.
• Crowe Luxembourg: Crowe Luxembourg is a mid-tier audit, tax, and advisory firm. It is comparable as a similarly positioned multi-line professional services competitor serving SME and mid-market clients in Luxembourg.

Others

• Odoo: Odoo is the cloud ERP platform with which GSL holds a Core strategic partnership powering its modern accounting offering. Comparable as the enabling technology partner underlying GSL's tech-led service model, rather than as a direct competitor.

Market position

Strengths5 records

Weaknesses5 records

Competitive moat4 records

Key risks6 records

Key highlights6 records

Customer concentration

Revenue estimate

Valuation estimate

Number of profiles

Profiles7 records

Funding overview

Funding rounds

Investors

Funding detail is available on the Subscription and Enterprise plan.Contact sales →

M&A

Investments

M&A and investment is available on the Subscription and Enterprise plan.Contact sales →

Frequently asked questions about GSL