What Companies House actually publishes

Every UK limited company has to appear on the public register. That single fact gets stretched into a lot of wrong assumptions about what you can find out about a business for free.

Here is the honest shape of it.

What you get

For every company on the register:

• registered name and company number
• current status, so active, dissolved, in liquidation, dormant
• date of incorporation
• registered office address, including postcode
• company type, private limited, LLP, and so on
• up to four SIC codes describing what it says it does
• filing history, and when the next accounts and confirmation statement are due
• officers, with roles and appointment and resignation dates
• people with significant control, so who ultimately owns or controls it

That is a lot. In particular, officers and control data is unusually open in the UK compared with most countries. You can see who runs a company, and you can find every other company those same people are involved in. That connection graph is the part people underuse.

What you do not get

• Turnover, profit or revenue, for most companies. Small companies file abridged accounts, and the overwhelming majority of companies are small. The numbers are simply not there.
• Employee numbers, for the same reason.
• Contact details. No phone, no email, no website. Ever.
• What the business actually does day to day, beyond a self-selected code.
• A trading address. The registered office is frequently the company's accountant, not the company.

The SIC code problem

This one deserves its own heading because so much gets built on top of it.

A company picks its own SIC codes at incorporation, from a dropdown, and nobody verifies the choice. Nobody makes them update it when the business changes either. So the codes are useful and they are not truth.

In practice that means two things. A SIC filter will miss companies that belong in your list, because they picked something adjacent or generic. And it will include companies that no longer do that thing, because they never went back to change it.

Treat SIC as a strong signal for grouping and a weak one for individual companies. It is excellent for "how many companies formed in this sector last year" and unreliable for "is this specific company a builder".

The thing that makes it valuable anyway

The register updates constantly, and incorporation appears immediately. A company that formed on Monday is public by the end of the week.

Almost no other business dataset moves that fast. Planning records lag by months. Land Registry lags by months. Company websites appear whenever someone gets round to it. If you want to know that something is happening rather than that it happened, formation data is usually the earliest public signal you can get.

What this means practically

The register is weak for financial qualification and strong for existence, structure, timing and connections. Build on the second and buy the first from somewhere else.

If you want to see the shape of it by sector, the sector view breaks the whole register down by SIC code, with formations and dissolutions.