What the matrix does not show
The three regimes are converging in some dimensions and diverging in others. Where they converge — climate disclosure increasingly aligned around TCFD-inherited concepts; Scope 1/2/3 GHG accounting broadly compatible across regimes — multi-regime reporters can build shared data infrastructure. Where they diverge — particularly on materiality (single in BRSR and IFRS; double in CSRD) — the data and reporting infrastructure must accommodate both perspectives.
For organisations subject to multiple regimes, the practical implementation question is whether to build to the most onerous regime and downscale for others, or to build differentiated reporting streams. The answer depends on entity-level circumstances — group structure, materiality of non-aligned disclosure dimensions, internal controls over sustainability reporting capacity.
Where assurance fits
Across all three regimes, assurance over sustainability reporting is increasingly important. BRSR Core requires reasonable assurance for the top 150 listed Indian entities. CSRD moves from limited to reasonable assurance over time. IFRS S1/S2 do not mandate assurance at the framework level but assurance is increasingly expected where jurisdictions adopt. Internal controls over sustainability reporting — analogous to ICFR for financial reporting — is the operational infrastructure that makes defensible assurance possible.
Currency note
Each of these regimes continues to evolve. CSRD scope and timing has been subject to EU-level adjustments. BRSR Core scope has expanded by tranche of listed entities. IFRS S1/S2 adoption is jurisdiction-by-jurisdiction. For binding application to a specific entity, confirm the current authoritative position with a qualified practitioner; the matrix above reflects the structural framework, not entity-specific applicability.