Call for tender – External audit services (2026-2028)

🗎 PDF: Call for tender Invitation to quote for external audit services (2026-2028)

Deadline for submission: 13 March 2026 – 23:59 CET

ECOS procurement and purchase policy

This call for tender is conducted in accordance with the ECOS Procurement and Purchase Policy, adopted by the ECOS Executive Committee and last updated in December 2024.

The policy sets out the principles of transparency, equal treatment, non-discrimination, and value for money, and defines the procedures applicable to competitive negotiated procurement processes.

It specifies thresholds relating to a competitive negotiated procedure with at least a specified number of candidates either with tender or selection, and sets out the procedure to be followed by ECOS. 

About ECOS

ECOS is an international NGO with a network of members and experts advocating for environmentally friendly technical standards, policies, and laws. We ensure the environmental voice is heard when they are developed and drive change by providing expertise to policymakers and industry players, leading to the implementation of strong environmental principles.

Background

ECOS is an AISBL registered in Brussels, located in the European district, and currently employs approximately 38 employees or trainees.

Revenue structure

ECOS’ revenues mainly consist of:

• Grants from the European Union, e.g. operating grants, action grants under programmes such as LIFE and Horizon Europe.
• Grants from private foundations and donors.
• Membership fees.

Cost structure

Main cost categories include:

• Staff and payroll-related costs.
• External experts.
• Direct project costs (travel, meetings, communication, etc.).
• General and administrative expenses.

Accounting and reporting systems

ECOS relies on the following systems:

• WinBooks for Belgian statutory accounting.
• WinBooks analytical accounting for project-based cost allocation.
• Bonotime for staff time tracking.

Objective of this tender

The purpose of this tender is to appoint an external audit firm through a framework contract for the provision of external audit services for a three-year period (financial years 2026, 2027 and 2028).

The appointment of the audit firm will be submitted for approval to the General Assembly of ECOS in June 2026.

Although ECOS is not legally required to appoint a statutory auditor under Belgian law, the General Assembly has decided to subject the annual accounts to an external audit, in line with good governance principles and donor requirements.

The framework contract will enter into force upon signature by the parties. Individual assignments will be governed by specific engagement letters.

Technical specifications

Indicative volume

Based on recent experience, the audit firm will mainly be requested to perform:

• Annual audit of ECOS statutory accounts (Belgian GAAP – BNB filing).
• Agreed-upon procedures or specific audits required by donors, including:
  • Certificates on the Financial Statements (CFS).
  • Interim or final audits for EU-funded projects, e.g. Horizon Europe, LIFE.
  • Other donor-specific audit or verification engagements.

Indicative financial volume (for information only):

• Annual total revenues currently in the range of EUR 4.9 million.
• EU operating grant of EUR 1.5 million.
• CFS audit on specific action grant of EUR 300,000.

These figures are indicative only and do not constitute a commitment. The actual volume will depend on ECOS’ activities and donor requirements during the contract period.

Scope of services

The requested services concern the provision of on-site and remote external audit services, in accordance with the International Standards on Auditing (ISA) and other applicable professional standards.

Under this framework contract, the Contractor will be required to:

• Perform the annual audit of ECOS’ statutory accounts for financial years 2026, 2027 and 2028, prepared in accordance with Belgian Generally Accepted Accounting Principles (Belgian GAAP), and issue an independent audit opinion on their reliability.
• Carry out donor-specific audit and verification assignments, including Certificates on the Financial Statements (CFS), agreed-upon procedures and other audit engagements required under EU-funded and privately funded grants, e.g. Horizon Europe, LIFE, operating grant, multi-annual action grants.

The number and nature of donor-specific audit assignments, including CFS, may vary from one financial year to another, depending on the grants awarded to ECOS and the related contractual requirements.

These assignments form an integral part of the scope of services covered by this framework contract.

ECOS commits to anticipate such assignments as far as reasonably possible and to ensure timely planning and clear communication with the Contractor. In return, the Contractor is expected to demonstrate adequate availability, flexibility and responsiveness, to meet donor-imposed timelines.

Each donor-specific audit assignment, including CFS, will be governed by a separate engagement letter, specifying the scope of work, timeline, deliverables and responsibilities.

The corresponding fees will be negotiated and agreed on a case-by-case basis, in line with the donor requirements and the terms of this framework contract.

Tasks

The main tasks include:

• Examining the reliability and accuracy of ECOS’ financial statements.
• Assessing whether accounting procedures are reasonable and compliant with applicable regulations and donor rules.
• Verifying that accounting records are properly maintained.
• Reviewing internal control systems and providing recommendations, where relevant.

Quality control arrangements

The audit firm must comply with:

• International Standards on Auditing (ISA).
• IFAC Code of Ethics for Professional Accountants, including independence requirements.
• International Standards on Quality Management (ISQM).

Audit working papers must be reviewed by a partner of the audit firm to ensure appropriate documentation and quality of audit conclusions.

For EU-funded projects, ECOS will act as the official contact point for any correspondence with EU institutions or the European Court of Auditors.

Audit team

The audit team must include at least:

• One audit manager.
• One or more qualified audit staff.

The team must demonstrate:

• Proven experience with NGOs and EU-funded projects.
• Familiarity with EU grant rules and donor-specific audit requirements.

The audit manager shall act as the primary contact person for ECOS and must be directly involved in the execution of the audit assignments.

Substantial parts of the audit work may not be delegated exclusively to junior staff without appropriate supervision. The audit manager shall be present during the main audit phases and review meetings.

Working language is English. Knowledge of other European language is considered an asset.

Tenderers must provide documentary evidence of staff qualifications and ensure continuity of the audit team throughout the contract duration.

Timeline

Tender preparation and submission

Tenderers are invited to submit a proposal by 13 March 2026 – 23:59 CET to: info@ecostandard.org

General information

• Legal name of the audit firm, registered address and contact details.
• Company profile and organisational structure.
• Designated contact person for the tender.
• Description of relevant experience, in particular with NGOs and EU-funded projects.

Audit team and methodology

• Proposed audit team, including roles, seniority and CVs of key staff.
• Confirmation that the audit manager will act as the primary point of contact and will be actively involved in the execution of the assignments.
• Description of the audit approach, quality assurance procedures and internal review processes.
• Measures ensuring continuity of the audit team throughout the duration of the framework contract.

Financial offer

Tenderers are requested to provide a transparent and detailed financial offer, including:

Statutory audit:

• Annual fee for the audit of ECOS’ statutory accounts.

Donor-specific audit assignments (including CFS)

For comparison purposes, tenderers are requested to provide:

• A schedule of hourly or daily rates per staff category (partner, audit manager, senior auditor, junior auditor).
• An indicative workload estimate (in hours or days per staff category), together with the resulting fee calculation, based on the rates provided, for the following illustrative scenarios:

Scenario 1 – Standard CFS

• Single beneficiary.
• Single cost centre.
• Limited number of staff involved.
• No subcontracting.
• Final financial report only.

Scenario 2 – More complex CFS

• Multiple beneficiaries or affiliated entities.
• Several cost centres and funding sources.
• Significant staff involvement and time allocation.
• Subcontracting and/or external experts.
• Interim and final financial reporting.

These examples are provided for evaluation and benchmarking purposes only and are non-binding.

The final scope, workload and fees for each donor-specific audit assignment will be negotiated and agreed on a case-by-case basis and formalised through a separate engagement letter, in accordance with donor requirements and the terms of the framework contract.

Evaluation criteria

Proposals will be evaluated by a selection committee using a predefined evaluation matrix.

Indicative award criteria:

• Experience and qualifications of the audit firm.
• Quality of methodology and quality assurance.
• Audit team composition and continuity.
• Cost and value for money (NGO context).

Attention will be paid to the proposed level of involvement of the audit manager and to the assurance of continuity of the audit team.