How do you find a company's subsidiaries?
For a US public company, open Exhibit 21 to its latest 10-K on SEC EDGAR, which lists subsidiaries and where each is organised. Then search GLEIF's LEI Search for the parent's direct and ultimate children (GLEIF), and check UK entities on Companies House, where a corporate owner appears on each subsidiary's record.
What is Exhibit 21?
Exhibit 21 is the list of subsidiaries a registrant attaches to its Form 10-K under Item 601(b)(21) of Regulation S-K. Most filers set it out as a table of names and jurisdictions of organisation, and some indent subsidiaries owned by another subsidiary (example Exhibit 21, SEC EDGAR).
The list is often incomplete by design. Filers may omit subsidiaries that, taken together as a single subsidiary, would not be a significant subsidiary; one 2019 exhibit states exactly that omission (Exhibit 21, SEC EDGAR). Significance is defined in Rule 1-02(w) of Regulation S-X (Exhibit 21.1, SEC EDGAR).
Step 1. Open the latest 10-K on SEC EDGAR
Search the company on SEC EDGAR, filter filings to 10-K and open the most recent one. In the filing index, find the document described as EX-21 or EX-21.1. Some groups list hundreds of entities; small companies may list a handful or state that they have none.
Step 2. Read the list for structure
Note each entity's jurisdiction. Delaware entities often hold US operations; entities in places such as the Netherlands, Luxembourg, Ireland or the Cayman Islands often sit in holding or financing chains. Indentation or footnotes show which subsidiary owns which. Compare 2 or 3 years of Exhibit 21 to see entities added, renamed or dropped, which can point to acquisitions, disposals or restructuring.
Step 3. Search GLEIF for the parent's children
Open GLEIF's LEI Search and find the parent's LEI. In simple mode, the "Who is owned by" filter returns entities whose reported parent matches your search; in expert mode, the Relationship menu offers Direct Children and Ultimate Children (GLEIF). GLEIF's Level 2 data follows accounting consolidation, so it shows entities consolidated into the parent's accounts (GLEIF, Level 2 data).
GLEIF fills 2 gaps in Exhibit 21. It covers groups that do not file with the SEC, and it can list children Exhibit 21 left out as not significant. It only includes entities that hold an LEI and reported their parent. How to find a company's LEI explains each field on the record.
Step 4. Check UK entities on Companies House
For each UK subsidiary, open its Companies House record and read the people with significant control tab. A company that controls a UK company, for example by holding more than 25% of shares or voting rights, is recorded there as a relevant legal entity (UK government PSC guidance, November 2025). This confirms the parent and gives the date control began.
For a UK parent, read the notes to its annual accounts in the filing history. UK companies must give information about related undertakings in the notes to their accounts under section 409 of the Companies Act 2006 (legislation.gov.uk). How to research a UK company on Companies House covers the filing history in detail.
Step 5. Combine and date the list
Merge the 3 sources into one list with each entity's legal name, jurisdiction, identifier (LEI or company number), parent and the source and date you found it in. Flag entities that appear in only one source. An entity in GLEIF but missing from the latest Exhibit 21 may have been judged not significant, sold or dissolved; check its status in the local register.
What do these sources not show?
None of them shows minority stakes below control, joint ventures the parent does not consolidate, or the individuals behind a private group. GLEIF records a reporting exception instead of a parent when an entity is controlled by a person. For owners rather than subsidiaries, follow how to find who owns a company.
Where does Tamarly Intelligence help?
Tamarly Intelligence is Tamarly's research platform on companies, funds, countries and markets, built from official filings and open data. It draws on SEC EDGAR, GLEIF and UK Companies House among its free and open sources, and every figure links to the filing or record it came from. When Tamarly does not cover a company it says so.
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Frequently asked questions
Where is the list of subsidiaries in a 10-K?
In Exhibit 21, filed with the 10-K under Item 601(b)(21) of Regulation S-K. On SEC EDGAR, open the 10-K filing index and look for the document labelled EX-21 or EX-21.1.
Does Exhibit 21 list every subsidiary?
No. Filers may leave out subsidiaries that, taken together, would not be a significant subsidiary, and many state this in the exhibit (Exhibit 21, SEC EDGAR). Check GLEIF and local registers for the rest.
How do you find subsidiaries of a private company?
Use GLEIF's "Who is owned by" search on the parent's name or LEI, then check national registers such as Companies House, where a corporate owner appears on each subsidiary's people with significant control record. A UK parent's annual accounts also give information on related undertakings.
About the author. Melvine Manchau is the founder of Tamarly and author of the Tamarly Newsletter. He previously worked at PwC, Salesforce, BlackRock/eFront and Lazard.
About Tamarly Research. Tamarly Research is part of Tamarly Media, which holds no investment positions. Tamarly is a New York research house that studies how AI is changing regulated institutions.