The EDGAR system
What is XBRL?
Updated
XBRL, short for eXtensible Business Reporting Language, is the tagging standard that makes SEC financial statements machine-readable. Every number in a modern 10-K or 10-Q carries an invisible label identifying exactly what it is: which concept (say, revenue from contracts with customers), which period, which unit, which segment. It is the reason software can compare revenue across a thousand companies without a human re-keying a single figure.
How it works
Tags come from a standard dictionary, the US GAAP taxonomy, maintained by the FASB and updated annually, which defines thousands of concepts with precise accounting meanings. A company maps each reported fact to a taxonomy element, adds context (period, entity, currency), and files the result alongside the human-readable document. When a company reports something the taxonomy lacks, it can create a custom extension tag. That flexibility is also the format’s biggest analytical headache, since extensions defeat cross-company comparison.
Inline XBRL
The tags are embedded in the filing’s own HTML document, a format called Inline XBRL (iXBRL), so one file is both human-readable and machine-readable. Opening a recent filing in the SEC’s viewer lets you click any number to reveal its tag, period and unit. Cover-page facts such as ticker, filer category and share counts are tagged too, and the requirements reach deep into the footnotes.
What it enables, and where it misleads
Tagged data sits behind almost everything built on filings: the SEC’s own company-facts tools, academic research, screeners, and products like Scrutar. The standardized statements on Microsoft’s financials page or NVIDIA’s exist because the underlying filings are tagged. Regulators use it to screen for anomalies at scale.
The caveats are real, though. Tagging errors happen: wrong signs, wrong periods, misapplied concepts. Custom extensions also vary widely in quality. Two companies may tag economically similar items differently, and restated figures can linger in derived datasets. Serious work treats XBRL as the index and the filing text as the authority: when a number matters, click through and read the statement it came from.
Adoption stretches well beyond the SEC: European issuers file annual reports in a similar inline format, and many other regulators collect data in XBRL.
The bigger picture
XBRL quietly converted EDGAR from a document warehouse into a structured database, one of the largest free financial datasets available. Every company in Scrutar’s directory sits on top of it.