Extension element
A custom tag a company defines for itself when no standard element fits its presentation.
Updated 2026-07-26
Extensions are permitted and often legitimate: a business with a genuinely unusual line has nowhere standard to put it. The cost is comparability, because an extension element exists in exactly one company's filings and matches nothing anywhere else.
A high proportion of extensions in a filing is a signal about how the data can be used, not a judgement about the company. It means that automated comparison with peers will miss part of the statement.
We never map an extension onto a standard element by guessing at its meaning. Either a filing states the standard element or the figure is presented under its own name.
Related terms
3 entries- US GAAP taxonomy
- The published dictionary of standard tags used for tagging U.S. financial statements, reissued each year.
- XBRL
- The tagging standard that turns figures inside a financial report into machine-readable facts.
- XBRL tag
- The named element that identifies what a tagged figure represents, such as Revenues or NetIncomeLoss.
Where this appears in the data
Written for reading the records published here. This is not a legal, tax or accounting definition, and where a jurisdiction defines the term precisely, that definition governs.