How it works
How CommonControl reaches each result, what it uses and what it can't see. You can refer to this page in a file note.
Who it's for
CommonControl is built for accountants and tax advisers working out a client's associated companies for the CT600, its group companies and whether it's a close company.
Company directors can use it too, to understand their own structure before speaking to their adviser. The results are a starting point, not tax advice, so check them with your accountant before relying on them.
The method
Trace the ownership
From the PSC registers we follow owners up to the ultimate owner and look for sister companies and subsidiaries, using a daily copy of the PSC register. Where a group runs through overseas companies, GLEIF's group records fill some gaps. Where a company files group accounts, we link to them: their notes list every subsidiary.
Apply the rules for the period
Associated at any time in the accounting period counts for the whole period. Dormant companies, possible passive holding companies and overseas companies are picked out, each with its evidence.
You settle what we can't see
Family links, commercial interdependence and whether two records are the same person need your knowledge. Answer the questions and the count updates. Your answers stay in your browser.
What the labels mean
Every company gets one of three labels, a reason in plain English and links to the records behind it. The headline count only uses companies we can count with confidence.
- Counted
- The records point to it being associated. It's in the headline count.
- Please check
- It may be associated, and we say why we can't tell. Shown separately, with a question where you can settle it.
- Probably not
- Likely excluded, for example dormant for the period, with the evidence.
2 associated companies
We found 2 associated companies for Example Trading Ltd for the period 1 April 2025 to 31 March 2026, plus 1 to check.
- Lower limit
- £16,667
- Upper limit
- £83,333
- CountedExample Holdings Ltd controls Example Trading Ltd.
- CountedSample Services Ltd: both are controlled by Example Holdings Ltd.
- Please checkOther Example Ltd: possible associate link, same surname and service address.
- Probably notDormant Example Ltd: dormant accounts filed for the period.
Group companies
The results list the companies in the same group, with the ownership worked out through the chain. The PDF report sets out the 51% group and the 75% group separately, with the holding at each step. Economic ownership (rights to profits and assets) can't be seen on the register, so the 75% group always says it hasn't been checked.
Sources
- Companies House public data: company profiles, officers, PSC registers and filing history
- Companies House's daily copy of the PSC register, to find companies owned by the same people or companies
- GLEIF group records, for groups whose companies have Legal Entity Identifiers
Every result shows when the Companies House data was retrieved, with a Refresh button.
What the register can't tell us
Public records only go so far. Where these matter, we say so and you may need to ask the client:
- Shareholdings of 25% or less, which aren't on the PSC register
- Family relationships and commercial interdependence between companies
- What overseas companies do, and who else they own
- Rights to profits and to assets on a winding up
- Companies owned through people who aren't named on any PSC register
This is a working aid, not tax advice.
How we handle data
- We don't record what you search for, and search terms stay out of our server logs.
- Your answers to our questions stay in your browser tab and are never sent to us.
- We keep Companies House data for up to 7 days, so anything removed there drops out within a week.
- No tracking cookies and no analytics.
See the privacy notice, and how to ask us to remove your details.