BRSR Core Assurance FY2026-27: A Readiness Roadmap for India's Top 1,000 Listed Companies
Indian listed companies are entering the final phase of SEBI's BRSR Core assurance glide path. From FY2026-27, the top 1,000 listed companies by market capitalisation must obtain either reasonable assurance or a third-party assessment of their BRSR Core indicators. For the 500 companies that joined the net after the top 500 were covered in FY2025-26, this is a first-time exercise with real audit-style scrutiny. Here is a practical roadmap for the months ahead.
Who is covered and what changed in 2025
The rollout has been phased: the top 150 companies from FY2023-24, the top 250 from FY2024-25, the top 500 from FY2025-26, and now the top 1,000 from FY2026-27. Coverage is decided by average market capitalisation, and the list as of 31 December 2025 determines who is in scope this year.
The March 2025 SEBI circular added a second route. Companies can now choose between assurance (typically under ISAE 3000 Revised, producing an opinion) and a third-party assessment against Industry Standards Forum (ISF) standards. The same circular made value chain disclosure fully voluntary, replacing the earlier comply-or-explain approach for the top 250. Treat the details here as a guide and confirm the final position against the SEBI circulars and the LODR master circular before you file.
The question is no longer whether your BRSR Core numbers will be tested. It is whether your data trail can survive the test.
The nine BRSR Core attributes
BRSR Core is a focused subset of the wider BRSR. Auditors and assessors will look at nine attributes:
GHG footprint (Scope 1 and Scope 2 emissions and intensity)
Water footprint
Energy footprint
Embracing circularity, including waste data
Employee well-being and safety
Gender diversity
Inclusive development
Fairness with customers and suppliers
Openness of business
Intensity ratios are calculated against revenue adjusted for purchasing power parity, so finance needs to own and document that number. For many companies, the GHG and energy attributes are where assurance providers spend the most time, because they depend on meter readings, fuel bills and a defensible Scope 2 method.
Choosing between assurance and assessment
Reasonable assurance gives you a formal opinion and carries the most weight with investors and lenders. Assessment is designed to cost less and ask less of your teams. Which route fits depends on your investor base, your data maturity and whether you already report under frameworks that expect assurance, such as CSRD for European subsidiaries.
The Board should record its choice of route in a minute, along with why the chosen provider has the right expertise. The provider need not be a Chartered Accountant.
Run a signed conflict check. The provider and its associates should not sell products or consulting services to the listed entity or its group companies.
Sign the engagement letter early so fieldwork can be scheduled for April and May 2027.
Where assurance providers will push hardest
Three areas tend to generate the most findings in a first assurance cycle.
Scope 2 is the first. Be ready to show a documented method and a register of renewable energy certificates, and report the gross figure. Our guide on Scope 2, RECs and carbon credits explains what can and cannot be claimed.
Scope 3 and supplier data is the second, even though value chain reporting is voluntary. Companies that choose to report need a list of partners making up 2% or more of purchases or sales, with disclosure limited to partners covering 75% of the total and the coverage percentage stated. Sectors with heavy upstream footprints, such as pharma, should start supplier data agreements now.
Boundary consistency is the third. The reporting boundary in Section A of the BRSR must match the provider's scope, and waste data that relies on vendor certificates needs documented reliance. Inconsistent boundaries are among the easiest findings to avoid.
A timeline you can work to
October to December 2026: confirm your market cap ranking, get Board approval on route and provider, complete the conflict check, and build an attribute register listing each KPI, its data owner, source system and evidence location.
January to March 2027: move to monthly data collection at every site, backfill April to December 2026 data, fix your Scope 2 method and boundary, and decide on value chain reporting.
April to May 2027: support provider fieldwork on the full year, sign management representations and review the draft statement.
With the annual report: publish the BRSR with the assurance or assessment statement, and complete the Section A disclosures naming the provider and the type of engagement.
Large corporates already show what mature disclosure looks like. Our analysis of Infosys's offset retirement disclosure shows how clear numbers and retirement records build credibility. If you are also tracking compliance pressure from the carbon market, read our October 2026 climate brief for the latest on CCTS and CBAM.
Where Csquare fits
Csquare helps Indian companies build assurance-ready emissions inventories, document Scope 2 and Scope 3 methods, and connect BRSR Core data with decarbonisation and carbon credit strategy. If your first assurance cycle is approaching and your data trail is not yet audit-ready, talk to our team about a readiness review.
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