BDO UK LLP (BDO UK), a leading accountancy and business advisory firm providing audit & assurance, tax and advisory services, engaged Simply Sustainable to deliver a double materiality assessment (DMA) to support its upcoming sustainability reporting. The company intends for greater alignment to the Global Reporting Initiative (GRI), which requires disclosure based on impact materiality, and prepare for the forthcoming UK Sustainability Reporting Standards (UK SRS), which are based on the IFRS Sustainability Disclosure Standards and address financial materiality, including climate-related risks and opportunities.
The DMA was designed to give BDO UK a clear understanding of its most significant environmental, social and governance (ESG) topics. It integrates stakeholder views with strategic priorities and provides a strong foundation for future disclosures and the development of a sustainability strategy.
Impacts and benefits
Stakeholder-validated insights: Engaged over 240 internal and external stakeholders via interviews and a survey to identify stakeholder perceptions of BDO UK’s key sustainability impacts, risks and opportunities.
GRI and IFRS alignment: Assessed 17 ESG topics using a dual-lens approach aligned to GRI 3: Material Topics (2021), which focuses on impact materiality, and IFRS S1/S2, which focuses on financial materiality. All topics were mapped to the relevant GRI standards to ensure future interoperability.
Clear focus areas for strategy and reporting: Identified 11 material sustainability topics across environmental, social and governance themes, each justified through stakeholder input and detailed impact, risk and opportunity analysis.
Foundation for future reporting: Produced a suite of outputs to support future GRI and IFRS disclosures, including a stakeholder engagement insights report, materiality matrix, impact-risk-opportunity register, and detailed rationale for material topic selection.
Actionable recommendations to support implementation: Outlined priority next steps to help BDO UK begin embedding material topics into governance, target-setting and strategy development, ensuring the DMA becomes an integral tool in advancing the firm’s sustainability journey.
The Simply Sustainable team brought structure, clarity and expertise to a complex process. The double materiality assessment has given us a credible foundation to further develop our sustainability reporting and strategy.”Claire Snowdon, ESG Lead, BDO UK
The story
Between November 2024 and June 2025, Simply Sustainable delivered a robust double materiality assessment for BDO UK, aligned with best practice. The assessment was undertaken as BDO UK looked to strengthen its sustainability reporting, both in preparation for upcoming UK and international disclosure requirements, particularly the UK SRS based on IFRS, and through voluntary alignment with the GRI. While sustainability was already a board-level priority, BDO UK recognised the opportunity to enhance its reporting approach by strengthening the underlying data and expanding stakeholder engagement. With recent efforts to align with GRI underway, and a new leadership team in place, BDO UK recognised that now was the right time to take a structured, evidence-based approach to understanding its most material ESG topics, across both impact and financial lenses.
We began by mapping BDO UK’s value chain across upstream suppliers, internal operations and downstream service delivery, including UK and international operations, BDO member firms, and the International Institutions and Donor Assurance (IIDA) business.
Seventeen sustainability topics were identified and refined using leading frameworks, including GRI, IFRS, and SASB, along with a review of peer and competitor disclosures to ensure sector relevance, and BDO UK’s business model. Topics were grouped into environment, social and governance themes and defined using GRI-consistent language to ensure continued alignment.
Stakeholder engagement was central to the process, including a stakeholder mapping workshop, 19 interviews with internal and external stakeholders (involving more than one participant in some cases), and a 209-person survey across BDO UK’s workforce, suppliers, clients and member firms.
Each topic was assessed for both impact and financial materiality. This began with the identification of relevant impacts, risks and opportunities across BDO UK’s operations and value chain. For impact materiality, we evaluated actual and potential effects across BDO UK’s value chain. For financial materiality, we assessed a range of risks and opportunities using BDO UK’s enterprise risk framework. Throughout the process, BDO UK was closely involved in reviewing the findings, participating in dedicated workshops to validate the assessment and provide additional context.
The result was a rigorous double materiality assessment, identifying a set of material ESG topics that reflect where BDO UK can deliver the most meaningful change, and are supported by detailed justifications, data-backed scoring, and stakeholder evidence. The outputs included a visual materiality matrix, full impact, risk and opportunity (IRO) register, stakeholder engagement insights report, and recommendations to inform future reporting and the development of a sustainability strategy. These outputs can also support broader efforts to integrate sustainability considerations into day-to-day decision-making and ways of working across the business.
The project was designed to integrate with BDO UK’s existing initiatives, including its enterprise risk management (ERM), UK climate risk analysis, global climate scenario analysis, and Taskforce on Nature-related Financial Disclosures (TNFD) readiness paper. The stakeholder insights also considered BDO UK’s existing listening channels, such as its Listening Survey. This integration ensures the DMA can serve as a foundational strategic tool to inform both sustainability reporting and the wider business strategy.
Outcome
BDO UK now has a stakeholder-led, data-driven understanding of its most material ESG topics, enabling the business to align future reporting with both GRI and IFRS. With a clear foundation in place, BDO UK is equipped to enhance its transparency, build trust with stakeholders and evolve its sustainability strategy with confidence.
This double materiality assessment provides a valuable reference point for informing future decisions and strengthening BDO UK’s approach to ESG disclosure and strategy over time.
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