An entity number lookup timeline: issue to retirement

An identifier is supposed to be the field that does not move. Mostly it is: that stability is why records are built around it rather than a name.

But "mostly" hides a handful of events that change it, and a handful more that change what it means without changing the string. This page is an entity number lookup timeline: the life story of a file number, from issue to retirement, and what to record at each turn.

What to take away

Issue

The office assigns the number when the entity is created on its register — in most states the Secretary of State, in Delaware the Division of Corporations — at the moment it accepts the formation filing, whether that is articles of incorporation, articles of organization, or a certificate of formation. It comes from that office's own series and format, and it means nothing anywhere else.

Two consequences follow immediately and hold for the record's life. A number is unambiguous only with its jurisdiction attached, and no other office will ever reuse or recognize it.

A file number is a state identifier, not a federal one. The IRS issues an employer identification number in the familiar XX-XXXXXXX form, on its own schedule and under its own rules; it never substitutes for the state file number, and neither number tells you anything about the other.

Some registers encode the entity type or the year of formation in a prefix — Delaware file numbers are seven figures with nothing in front of them, while a Companies House company number is eight characters and may open with a letter. Read the type from the record rather than decoding the prefix, because encodings change and a decoded prefix is a guess about the register's history.

The long middle, where nothing happens to the number

Most of an entity's life leaves the identifier untouched. The registration is a legal person in its own right, in the sense the Legal Information Institute sets out under corporation, and that person persists while everything attached to it changes.

This is why a record built on the identifier survives a decade and a record built on the name does not.

The events that can change it

Conversion. The entity changes type, and in every state this is a statutory filing rather than a formality — the Delaware General Corporation Law carries its own conversion provisions, and the Model Business Corporation Act is the template many state corporation acts follow. The filing is an articles of conversion, or a certificate of conversion, made with the office that will hold the surviving record. A register may treat the result as a continuation under the old number or as a new entity with a new one. The filing history distinguishes them: a conversion row followed by the same number is continuation; a fresh formation row is a new entity.

Domestication. The entity moves its home state, again by statute, filing articles of domestication in the receiving state. That state issues its own number, and the original state's record ends, typically with a withdrawal or a surrender. Two numbers, two records, one company, and no cross-reference in either direction.

System migration. An office replaces its register and renumbers, or reformats, or both. A Secretary of State that moves to a new filing system normally posts a notice and, where renumbering was unavoidable, a conversion table on its own site. Old numbers may still resolve, may redirect, or may fail. This is the one change nobody at the company caused and nobody at the company was told about.

Re-formation after a terminal lapse. A company that let a lapse run past the office's reinstatement window and formed a new entity has a new number and a new formation date, whatever the name and the letterhead say. This is not a change to an identifier. It is a different entity wearing a familiar name.

Retirement

When an entity is dissolved — the office accepts articles of dissolution, or the equivalent, and closes the record — the record generally stays on the register and the number stays attached to it. Registers do not, as a rule, reassign a retired number, and "as a rule" is a policy of each office rather than a law of nature.

Where it matters, search the number and read the formation date: a recent date under a number quoted on an old document means the number was reissued and the earlier entity has to be found by name.

Records occasionally leave the public index entirely, usually because a series is no longer displayed. A number that returns a blank page rather than a not-found is the usual sign.

A chronology worth keeping

For any entity you rely on, keep the identifier as a small history rather than a single cell.

A row per identifier carries, at minimum, the number itself, its jurisdiction, the entity name it was filed under at the time, the event that prompted the entry, and the date you last confirmed it against the office's record. The register holds the fact; your row holds the date you looked.

Closing a row rather than overwriting it is the whole discipline. Old contracts, invoices, and credit files quote retired numbers for years, and the closed row is what lets somebody recognize one.

What a chronology is good for

It cleanly answers a narrow set of questions: which record a historical document refers to, whether two numbers belong to one continuing entity, and when your own information about each was last confirmed.

It answers nothing about the business and should not be extended to try. Where the chronology feeds a decision, the judgments belong in the sequence set out in company verification.

Registers that publish programmatic access state plainly which identifiers they undertake to keep stable, and the Companies House developer overview is a clear example of that promise being made explicitly. Where a register makes no such promise, assume the string is stable in practice and unguaranteed in principle, and keep the confirmation dates that let you notice if it moves.

Common questions

How would I even find out that a register renumbered?

Usually by a search failing on a number that worked before. Offices publish migration notices, often briefly, so check the register's own news or help pages before assuming the entity is gone.

Two numbers, and the register says nothing about the link. Can I join them?

Only from a document: the conversion or domestication filing, a certificate the company supplied, or a contract quoting both. A name match is not a link, and this is exactly the case the entity number lookup pillar warns about.

Does the formation date move when the number does?

On a continuation, no. On a new entity, everything is new including the date, which is why the pair should always be read together rather than either alone.

Should I store the retired number in the same field?

No. Keep one row per identifier with its own dates. A single field holding two numbers is unqueryable, and the point of the chronology is that a stranger can read it.