Why sustainability assurance is gaining attention
Sustainability reporting is moving from voluntary to mandatory. Companies around the world are being required to disclose their environmental, social, and governance (ESG) performance. Investors, regulators, and customers want to know how businesses manage their impact on the planet and on people.
In South Africa, the Independent Regulatory Board for Auditors has adopted ISSA 5000, General Requirements for Sustainability Assurance Engagements, along with ethics standards for sustainability assurance. This means South African auditors will be able to perform independent assurance on sustainability reports and disclosures.
For businesses, this creates both an obligation and an opportunity. Companies that prepare for sustainability assurance now will be better placed when mandatory reporting requirements arrive.
What ISSA 5000 is
ISSA 5000 is the International Standard on Sustainability Assurance. It provides the framework for auditors and assurance practitioners to perform assurance engagements on sustainability reports and other sustainability-related disclosures.
The standard covers:
- General requirements for sustainability assurance engagements
- The practitioner’s responsibilities when planning and performing the engagement
- The requirements for evaluating evidence and forming a conclusion
- The content and format of the assurance report
ISSA 5000 is designed to work alongside existing assurance standards. It applies to assurance on sustainability reports, climate-related disclosures, ESG metrics, and other sustainability information.
What the IRBA has adopted
In February 2026, the IRBA adopted:
- ISSA 5000: General Requirements for Sustainability Assurance Engagements
- Ethics Standards for Sustainability Assurance (including independence standards): New Part 5 of the IRBA Code of Professional Conduct
These standards are equivalent to the ethical and independence requirements that apply to financial statement audits. This means sustainability assurance will be held to the same high standard as audit.
The standards are included in the 2025 Handbook Volume III and are effective from 15 December 2026, except for provisions applicable to value chain components which will be effective from 1 July 2028.
What this means for South African businesses
Listed companies
JSE-listed companies are already subject to King IV requirements on integrated reporting. The adoption of ISSA 5000 means that sustainability assurance on integrated reports will be conducted under a recognised international standard. This enhances the credibility of sustainability disclosures and aligns South African practice with global developments.
Private companies
While private companies are not currently required to produce sustainability reports, the trend is toward broader adoption. Banks, investors, and supply chain partners are increasingly asking for ESG information. Having sustainability assurance available strengthens your position when dealing with these stakeholders.
State-owned companies and government entities
Public sector organisations are also moving toward sustainability reporting. The adoption of ISSA 5000 provides the framework for assurance on these reports.
The key elements of sustainability assurance
Subject matter
Sustainability assurance can cover a wide range of topics:
- Environmental metrics (carbon emissions, water usage, waste management)
- Social metrics (employment equity, health and safety, community impact)
- Governance metrics (board composition, ethics, risk management)
- Climate-related financial disclosures (aligned with TCFD or ISSB recommendations)
Criteria
The assurance practitioner evaluates the sustainability report against defined criteria. These may include:
- The Global Reporting Initiative (GRI) standards
- The International Sustainability Standards Board (ISSB) standards
- The King IV Code on Corporate Governance
- Company-specific sustainability policies and targets
Level of assurance
Sustainability assurance may be performed at two levels:
- Reasonable assurance: The practitioner obtains sufficient appropriate evidence to provide a high level of assurance (similar to a financial statement audit)
- Limited assurance: The practitioner performs fewer procedures and provides a lower level of assurance (similar to an independent review)
Evidence
The assurance practitioner gathers evidence through:
- Inquiry of management and relevant personnel
- Observation of processes and practices
- Inspection of documentation and records
- Analytical procedures
- External verification of data (e.g., emissions data from independent sources)
How to prepare for sustainability assurance
Step 1: Start reporting
If your business does not currently produce a sustainability report, start now. You do not need a formal report to begin. Start by tracking key metrics:
- Energy consumption and carbon emissions
- Water usage
- Waste generated and recycled
- Employee demographics and transformation metrics
- Health and safety incidents
- Community investment and social impact
Step 2: Align with recognised frameworks
Choose a reporting framework that fits your business. The most common frameworks are:
- GRI Standards: Comprehensive sustainability reporting framework used by thousands of organisations worldwide
- ISSB Standards: Focus on financially material sustainability information for investors
- King IV: Corporate governance framework applicable to all South African organisations
Step 3: Establish data processes
Sustainability assurance requires reliable data. Establish processes for collecting, verifying, and reporting sustainability data. This may involve:
- Assigning responsibility for sustainability data collection
- Implementing systems for tracking metrics
- Establishing internal review processes for data accuracy
- Documenting data sources and methodologies
Step 4: Engage with your assurance provider
Talk to your auditor or assurance provider about sustainability assurance. Understand what the engagement will involve, what data will be needed, and what the timeline looks like.
Step 5: Integrate with financial reporting
Sustainability reporting and financial reporting are converging. The ISSB standards link sustainability information with financial performance. Consider how your sustainability data integrates with your financial reporting processes.
The business case for sustainability assurance
Investor confidence
Investors increasingly use ESG information to assess risk and make investment decisions. Assured sustainability reports provide investors with confidence that the information is reliable and comparable.
Regulatory preparedness
Mandatory sustainability reporting is coming. Companies that prepare now will be ahead of the curve when regulations take effect.
Risk management
Sustainability reporting forces you to identify and measure your environmental and social risks. This information is valuable for strategic planning and risk management.
Competitive advantage
Businesses with strong sustainability credentials attract customers, employees, and partners who share those values. Sustainability assurance demonstrates that your claims are verified and credible.
The bottom line
Sustainability assurance is no longer a niche concern. The IRBA’s adoption of ISSA 5000 and ethics standards for sustainability assurance signals that South Africa is aligning with global developments. Businesses that prepare now will be better placed to meet the expectations of investors, regulators, and customers.
Starting with basic sustainability tracking and aligning with recognised frameworks are practical first steps. The assurance process builds on this foundation, providing the independent verification that stakeholders increasingly expect.
SC Audit is an IRBA-registered audit firm based in Bellville, Cape Town. SC Audit’s partners Niel Schoeman, Simone Coetzee, and Hennie Meyer support businesses with sustainability reporting, assurance readiness, and ESG strategy. Contact SC Audit to discuss how sustainability assurance fits into your business strategy.
Frequently Asked Questions
What is ISSA 5000?
ISSA 5000 is the International Standard on Sustainability Assurance. It provides the framework for auditors to perform assurance engagements on sustainability reports and other sustainability-related disclosures. The IRBA adopted ISSA 5000 in February 2026.
Do I need to produce a sustainability report?
There is currently no mandatory requirement for private companies to produce sustainability reports in South Africa. However, banks, investors, and supply chain partners are increasingly asking for ESG information. Starting to track and report sustainability data positions your business for future requirements.
What is the difference between reasonable and limited assurance?
Reasonable assurance provides a high level of assurance, similar to a financial statement audit. Limited assurance provides a lower level of assurance, similar to an independent review. The level of assurance depends on the engagement scope and the needs of the stakeholders.
When do the IRBA sustainability assurance standards take effect?
The standards are effective from 15 December 2026, except for provisions applicable to value chain components which will be effective from 1 July 2028.
What frameworks should I use for sustainability reporting?
The most common frameworks are GRI Standards, ISSB Standards, and King IV. The right framework depends on your stakeholders, your industry, and the information you want to disclose. GRI is the most comprehensive; ISSB focuses on investor-relevant information; King IV covers governance.