A Practical Guide to Companies House Data for Accountants

Most accountants know Companies House as the place you look up a company number or check a filing deadline. But Companies House data can be used well beyond individual lookups for accountants. The register holds structured, publicly available records on every limited company in the UK, including every company incorporated yesterday, last week, and last month.

This guide covers what data is available and which fields matter most for accountancy practices. To help you shift from using Companies House reactively to proactively, finding relevant new companies before they find an accountant.

What Companies House Actually Holds

Companies House is the UK's registrar of companies. It maintains a public register of every limited company, limited liability partnership (LLP), and other entities registered in England, Wales, Scotland, and Northern Ireland. At the time of writing, that register covers millions of companies, both active and dissolved.

The data falls into several broad categories:

• company details (name, number, registered address, status)
• officer information (directors, secretaries, and their service addresses)
• filing history (accounts, confirmation statements, and other statutory documents)
• charges (mortgages and security interests registered against the company)
• persons of significant control (PSC) data

Data Fields That Matter to Accountants

Not every field on the register is equally useful for practice development. If you're looking to identify and reach new companies, six fields do most of the work:

Company name and number. The basics. The company number is the unique, permanent identifier. Useful for cross-referencing and record-keeping.

SIC codes. Every company must select at least one Standard Industrial Classification code at incorporation. These codes describe the company's stated business activity and are the primary way to filter companies by sector. A practice that specialises in construction clients, for example, can filter for SIC codes in the 41–43 range. For a full explanation, see our guide to SIC codes explained.

Registered office address. This tells you where the company is based or at least where its official correspondence goes. For local and regional practices, this is how you filter by geography.

Director names and service addresses. You'll know who's running the company from day one. Service addresses are public; residential addresses are protected by default.

Filing deadlines and history. As the company matures, its filing history grows. Confirmation statements, annual accounts, and other submissions appear on the register as they're filed.

Incorporation date. This tells you exactly how new the company is and whether you're reaching the director in the window where they're still making decisions about professional services.

Reactive vs Proactive Use

Most accountants use Companies House reactively. Someone mentions a company in a meeting, you look it up. A prospect gives you a company name, you check their filing history. A client asks about a competitor, you pull their latest accounts. This is valuable and it's what the register was designed for.

But there's a second way to use the same data. Instead of waiting for a company name to come to you, you go looking for companies that match your practice's target profile. This is where Companies House public data shifts from a reference tool to a practical source of new business opportunities.

New Incorporation Data Represents An Opportunity

Every day, Companies House publishes data on every newly incorporated limited company in the UK. Company name, SIC codes, registered address, director names, all available from the day of incorporation. This daily flow of new data is what makes proactive use possible. .

The volume is significant. Hundreds of new companies are incorporated across the UK each day. Without filtering, that's noise. With the right filters like sector, location, or both, it becomes a manageable, relevant list of companies you can act on each week.

The practical question isn't whether the data is available. It is, and it's free. The question is how you filter it down to the companies that matter to your practice and how quickly you can do it.

Accessing the Data

There are three broad ways to access Companies House data, each suited to different needs and technical comfort levels.

Manual Search (One Session at a Time)

The Companies House website includes a basic and advanced search that lets you filter companies by incorporation date, SIC code, and registered office postcode area. It's free and covers the same public data as any other source. The limitation is workflow: there are no saved searches, no scheduled runs, and no way to have results delivered to you automatically. Every time you want an update, you repeat the process manually. For tips on getting the most from it, see our guide to how to search Companies House effectively.

Bulk Data Products

Companies House publishes free bulk data products including a full snapshot of the register, released as a CSV download. It's more accessible than it sounds with no API required. The limitation is timing: snapshots are updated monthly, so if a company incorporated last week, it won't appear in bulk data until the next release cycle. For practices that want to act early, that gap matters. .

Filtered and Packaged Services

The middle ground is a service that does the filtering for you. LaunchRegister, for example, filters daily incorporation data by SIC code and postcode area, then delivers matched results to your inbox as a simple CSV. We set the search profiles you want whether sectors or particular and you receive a digest on a daily or weekly schedule. No bulk data to wrangle, no developer skills required. See how LaunchRegister packages this data for a full walkthrough of the workflow.

Frequently Asked Questions