ISSB Global Adoption Tracker: Where Does Turkey Stand?

One Global Standard, Many Adoption Paths

The International Sustainability Standards Board (ISSB) published IFRS S1 and IFRS S2 in June 2023. S1 establishes the general framework for sustainability-related financial disclosures, while S2 addresses climate-specific disclosures. The International Organization of Securities Commissions (IOSCO) endorsed these standards in July 2023 and recommended that member jurisdictions adopt them (IOSCO, Endorsement of ISSB Standards, July 2023).

However, a global standard does not mean uniform adoption. Each country is choosing a different adoption model based on its legal infrastructure and market conditions. This article maps the global adoption landscape and assesses where Turkey stands within it.

Adoption Models

According to the IFRS Foundation's Jurisdictional Guide, countries are adopting the ISSB standards through three primary models (IFRS Foundation, Jurisdictional Guide to ISSB Standards, 2024):

Full Adoption

Incorporating standards into national legislation as-is or with minimal modifications. Standards become a direct part of the legal framework.

Adapted Adoption

Adopting standards with adaptations to the national context. Core principles are preserved while local requirements are added or specific provisions are modified.

Building Blocks Approach

Using ISSB standards as a foundational building block while developing national standards independently. The EU's ESRS approach is closest to this model.

The Global Adoption Map

Jurisdictions with Mandatory Adoption

Turkey — The Public Oversight Accounting and Auditing Standards Authority (KGK) adapted IFRS S1 and S2 as the Turkey Sustainability Reporting Standards (TSRS). TSRS 1 and TSRS 2 became mandatory for public interest entities starting in 2024. Turkey is one of the first G20 countries to set a mandatory implementation timeline for ISSB standards (KGK, TSRS Communiques, 2023).

Nigeria — The Financial Reporting Council (FRC) made ISSB standards mandatory for certain company categories from 2025. Nigeria stands out as the first African economy to adopt the ISSB.

Brazil — The Comissão de Valores Mobiliários (CVM) announced that ISSB-aligned sustainability reporting will become mandatory on a phased basis starting in 2026. As Latin America's largest capital market, Brazil's decision sends regional signals.

Jurisdictions in Advanced Preparation

United Kingdom — The Financial Conduct Authority (FCA) is developing UK Sustainability Disclosure Standards. High alignment with ISSB is targeted, with adaptations specific to the UK capital market. First mandatory reporting is expected in 2026 or 2027.

Japan — The Sustainability Standards Board of Japan (SSBJ) published national standards aligned with ISSB. Mandatory implementation for Tokyo Stock Exchange prime market companies is envisaged from 2027.

Australia — The Australian Accounting Standards Board (AASB) published AASB S1 and S2, adapting the ISSB standards. Mandatory reporting begins for large entities in 2025 and expands in phases.

Canada — The Canadian Securities Administrators (CSA) are working on ISSB-aligned disclosure rules. The Canadian Sustainability Standards Board (CSSB) is in the process of developing national standards.

Jurisdictions Taking a Different Approach

European Union — Rather than directly adopting ISSB, the EU developed its own standard set (ESRS). ESRS is broader in scope than ISSB, incorporating a double materiality approach, but interoperability work between ESRS and ISSB continues (EFRAG-ISSB Interoperability Guidance, 2024).

United States — The SEC's Climate Disclosure Rule faced legal challenges. The US has not officially adopted ISSB, although California enacted its own state-level climate disclosure laws.

Turkey's Pioneering Position

TSRS: The Adapted Adoption Model

Turkey adopted ISSB standards through an "adapted adoption" model. KGK did not merely translate IFRS S1 and S2 into Turkish; it adapted them to the Turkish business environment and regulatory landscape. In this adaptation process:

• Core principles and disclosure requirements were preserved
• Phased transition provisions were added, considering Turkish companies' reporting capacity
• Integration with KGK's existing audit and oversight infrastructure was ensured

Why It Matters

Turkey's early adoption decision is strategically significant for several reasons:

International investor confidence. Companies reporting in line with ISSB meet international investor expectations. TSRS reports from Borsa Istanbul-listed companies provide global comparability.

EU trade relations. The EU, Turkey's largest trading partner, requires comprehensive sustainability reporting through CSRD/ESRS. TSRS alignment makes it easier for Turkish suppliers to meet their EU customers' data demands.

Regional leadership. Turkey is the first economy in its region (Middle East, North Africa, Central Asia) to make ISSB mandatory. This position strengthens the international reputation of the Turkish capital market.

Comparison with Peer Economies

What Lies Ahead

2025 and 2026 will be decisive years for ISSB adoption. As the United Kingdom and Japan finalize their mandatory implementation timelines, ISSB's global coverage will expand significantly. According to data published by the IFRS Foundation in late 2024, more than 60 percent of the world's capital markets are in the process of adopting or actively evaluating the ISSB.

Turkey can leverage its pioneering position to both enhance the international competitiveness of its companies and become a regional knowledge and experience hub.

Key Takeaway: TSRS alignment is not merely a reporting obligation — it is a strategic opportunity. Early adoption experience makes Turkish companies more attractive to global investors and trade partners.

See how enterprise teams align their reporting with ISSB standards.