Every number in a modern financial report carries a label saying what it is, what period it covers, whose it is and in what units it is stated. That labelling is what makes it possible to read a filing without a human retyping tables.
What a tag carries
A tagged fact has four parts that matter for reading it:
- The element — the named concept, drawn from a published dictionary, such as an element for revenue or for net income.
- The period — an instant for balance sheet items, a span for flows.
- The entity — which reporting entity the figure belongs to.
- The unit — currency, shares, or a pure number.
A figure without its period and unit is not usable. A figure whose period was assumed rather than read is worse than unusable, because it looks fine.
Why two companies tag the same line differently
The dictionary offers real choices. Revenue can be tagged with a general element or with a narrower one depending on how a company presents its business, and both can be correct under the accounting rules while producing series that should not be laid side by side without checking.
Companies may also define their own elements when nothing standard fits their presentation. Such an extension is legitimate and often unavoidable, and it matches nothing in any other company's filings. A statement full of extensions is not worse reporting; it is reporting that automated comparison will partly miss.
The dictionary itself changes
The standard taxonomy is reissued annually. Elements are added, renamed and retired, and each filing states which version it used. A long series assembled across versions can show a break that has nothing to do with the business — only with the dictionary.
What this site does
Every figure taken from a tagged filing is shown with the element name it came from and the filing it came from. That is deliberate: it lets a reader see whether two numbers are actually the same measure before treating them as comparable.
We never map a company's own extension onto a standard element by guessing at what it means. Either the filing states a standard element or the figure appears under its own name.