TSRS: the assurance period in sustainability reporting
Sustainability reporting is no longer a voluntary communications exercise; for businesses above defined thresholds it is a standards-based obligation subject to assurance.
The Turkish Sustainability Reporting Standards (TSRS) require businesses to report sustainability-related risks and opportunities with the same discipline as their financial statements. Issued by the Public Oversight, Accounting and Auditing Standards Authority, they align with the international reporting framework.
Who falls within scope?
Scope covers the institutions listed by the Authority together with businesses exceeding size criteria. At least two of the criteria must be exceeded in two consecutive reporting periods; exceeding them in a single period does not by itself create an obligation. The Authority's decision published in the Official Gazette on 16 January 2026 updated the thresholds, applying to periods beginning on or after 1 January 2025.
| Criterion | How it is assessed |
|---|---|
| Total assets | Balance sheet size, two consecutive periods |
| Annual net turnover | Income statement, two consecutive periods |
| Number of employees | Average headcount, two consecutive periods |
| Listed institutions | Entities in the Authority's list are directly in scope |
What must be reported?
- Governance: the body and processes responsible for overseeing sustainability-related risks and opportunities.
- Strategy: the effect of those risks and opportunities on the business model, value chain and financial position.
- Risk management: how risks are identified, assessed and prioritised.
- Metrics and targets: the indicators used, the targets set and performance in the period.
- Climate-related disclosures: greenhouse gas emissions together with transition and physical risks.
The assurance dimension
Sustainability reports are subject to assurance under principles set by the Authority, carried out in accordance with the assurance engagement standards. In practice this means the content is examined independently and its supporting evidence is sought; documented data replaces marketing language.
What this requires on the accounting side
- Identifying data sources: energy, fuel, water and waste data usually sit outside the accounts and must become regular and traceable.
- Matching invoices with consumption: most emission calculations rest on invoice data already held in the accounts.
- Value chain information: the method for collecting supplier and subcontractor data must be designed from the outset.
- Periodicity: the sustainability report must use the same period and reporting boundaries as the financial report.
- Documentation: the calculation method and source of every indicator must be written down; it is the first thing requested in assurance.
The subject is not remote even for businesses outside scope. If you supply a company that is in scope, being asked for data for its value chain disclosures is routine. Before that request is written into a contract, it should be clear which data, by which method and at what frequency will be provided.
Legal basis
- Turkish Sustainability Reporting Standards (TSRS 1 and TSRS 2)
- Authority decisions on the scope of application — Official Gazette, 16 January 2026
- Authority decision of 5 September 2024 on assurance
- Assurance Engagement Standards (GDS 3000, GDS 3410)
This article is general information and does not replace professional assessment of a specific matter. Amounts and rates relate to the stated year; please verify the current provisions before acting.
