How We Use the Companies House API for B2B Data Enrichment
A contact file tells you who someone is. B2B data enrichment tells you whether they're worth talking to.
Knowing a prospect's job title is a starting point. But knowing their company's financial health, how many directors it has, whether it carries outstanding debt, or how many employees it runs - that's the kind of intelligence that sharpens targeting, improves relevance, and drives better campaign results.
At Emailmovers, we've built an automated B2B data enrichment pipeline that appends verified company data directly to your contact files, at scale, with no manual work required.
Here's how it works.
What is the Companies House API?
Companies House is the UK government's official register of limited companies. Every UK company is legally required to file information there - from basic incorporation details through to annual accounts, director appointments and charges against company assets.
The Companies House API provides programmatic access to all of this data. We've built tooling on top of it that can take your existing data file - even one with tens of thousands of records - and enrich it automatically, supporting large-scale B2B data enrichment and returning a clean, appended file ready to use in your campaigns or CRM.
What data can we append?
Depending on your requirements, we can enrich your file with up to 30 fields, drawn from Companies House and our own 360 company database - forming a complete B2B data enrichment layer.
From Companies House:
- Company status (active, dissolved, dormant)
- Incorporation date
- SIC codes (industry classification)
- Registered office address
- Number of active directors
- Whether the company has charges (secured debt) registered against it
- Outstanding vs satisfied charges, including charge holder names
- Insolvency history
- Accounts type (full, micro, or dormant)
- Shareholder funds / net assets
- Current assets and current liabilities
- Average number of employees
- Accounts period end date
From our 360 company database:
- Employee count and employee range
- Revenue and revenue range
- Industry and sector classification
- Company description
- Website and LinkedIn URL
- Parent company and corporate hierarchy
Financial data is extracted directly from iXBRL filings - the structured electronic accounts that UK companies are required to submit. This means we're reading from the source, not estimating.
Case Study 1: Charges Lookup at Scale
One recent project involved a contact file of over 11,000 records spanning nearly 6,000 unique companies. The client needed to know which companies had outstanding charges registered against them - active secured debts such as bank loans, commercial mortgages, asset finance or invoice financing arrangements.
A charge is a legal claim registered against a company's assets as security for a debt. An outstanding charge means the debt is still active. A satisfied charge means it has been repaid. For the right audience - financial services, asset finance, business recovery - this is a powerful targeting signal.
Our pipeline deduplicated the file to 5,879 unique company registration numbers, made one API call per company, then mapped the results back to all 11,031 rows - a practical example of B2B data enrichment at scale.
Every contact record at the same company received the same enriched data automatically.
Results:
- 11,031 contact records processed
- 54% of unique companies had outstanding charges
- Zero errors
The output included four new columns: has_charges, total_charges, outstanding_charges, and satisfied_charges - appended directly to the original file.
Case Study 2: Full Company Enrichment
A second project took a different approach. Starting from a list of nearly 1,900 company names - no registration numbers, just names - we returned a fully enriched file with up to 30 data fields per company as part of a full B2B data enrichment process.
This involved matching each company name against the Companies House register, retrieving the full company profile, downloading and parsing the iXBRL financial filings and cross-referencing against our 360 database - all in a single
automated run.
Results:
- 1,891 companies processed
- 99.9% match rate on Companies House
- Financial data (shareholder funds, assets, liabilities) retrieved for over 60%
of companies - Director counts returned for 99.9% of companies
The enriched file gave the client a dataset they could immediately segment by financial profile, company size and industry - without a single manual lookup.
How AI Powers The Process
The enrichment pipeline was designed and built using AI-assisted development, which allowed us to move from concept to a working, production-ready tool in a single session - and to iterate quickly as client requirements evolved.
When a second project needed a different approach (charges-only, at higher volume), we adapted the tooling without rebuilding from scratch. When edge cases emerged - encoding issues, rate limits, companies with multiple contacts in the same file - the pipeline handled them automatically.
AI didn't just speed up the build - it made the tooling more robust and adaptable than a traditionally developed script would typically be, enabling faster and more flexible B2B data enrichment workflows.
Who is this for?
This service is particularly well suited to clients with complex or bespoke B2B data enrichment requirements - situations where off-the-shelf data products don't quite fit.
If you have an existing file and need it enriched with specific company intelligence, if you need to segment by financial health or debt profile, if you're working with niche industries or unusual targeting criteria, or if you simply need a large file processed quickly and accurately - this is the kind of project we're set up to handle.
We'll review your file, confirm which fields are available and at what match rate and provide a sample output before you commit to a full run.
Get in Touch
If you have a B2B data enrichment requirement - however specific- we'd be happy to discuss it.
Get in touch with the Emailmovers team and we'll let you know what's possible.
Get In Touch With Us!
Call us on 01723 800030