XBRL (eXtensible Business Reporting Language)

XBRL (eXtensible Business Reporting Language) is a standardised digital format for business and financial reporting. Under the CSRD, all sustainability reports must be tagged in XBRL format to enable machine-readable, comparable disclosures across the EU.

XBRL works by assigning standardised tags to each piece of data in a report. For example, a company’s Scope 1 emissions figure would be tagged with a specific XBRL taxonomy element, making it instantly identifiable and comparable by software systems , regardless of where it appears in the report or what language it’s written in.

For CSRD reporting, the XBRL taxonomy is based on the ESRS datapoints. This means every required disclosure has a corresponding digital tag.

Key implications for companies:

• Reports must be submitted in Inline XBRL (iXBRL) format , a human-readable document with embedded digital tags
• The taxonomy is maintained by EFRAG and aligned with ESRS updates
• Most companies will need specialised software or service providers to handle XBRL tagging
• National registries accept XBRL submissions as part of the annual filing process

While XBRL may seem like a technical footnote, it represents a significant shift toward structured, comparable sustainability data across the European market.