XBRL & ESEF

Anchoring

Also known as: Wider anchoring · Narrower anchoring

Linking a company-specific extension element back to the closest element in the base taxonomy, by accounting meaning, so the extension stays interpretable.

What it means

Anchoring links a preparer-created extension element to the most closely related element(s) in the base ESEF/IFRS taxonomy, using “wider” and “narrower” accounting-meaning relationships. It is what lets a reader place a company-specific concept inside the standard taxonomy and compare it across filers. ESMA's ESEF Reporting Manual gives anchoring dedicated guidance.

Wider vs narrower anchoring

Wider anchoringNarrower anchoring
WhenAlways, for every extension element.Only when the line item combines two or more base concepts.
Links toThe closest base element that fully encompasses the extension's meaning.The closest base element(s) narrower than the extension.
PurposePlace the custom concept within the standard taxonomy.Show what the combined figure is built from.
Every extension needs at least one wider anchor; narrower anchoring is required only when an extension combines several base concepts.

How it relates to nearby concepts

Anchoring is the safety net for extensions created during tagging. Without it, an extension element would be an island that comparison tools could not interpret.

Common misunderstandings

  • Anchoring just means linking to any similar concept: It means the closest wider (and, when combining concepts, closest narrower) element by accounting meaning and scope.

Sources

Last reviewed: 19 June 2026

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