What is a SIC code?
How do SIC codes work?
SIC codes classify businesses by economic activity in a hierarchy. Each five-digit code sits inside a class, group, division (the first two digits) and a lettered section. For example, 62020 "Information technology consultancy activities" is in division 62, computer programming and consultancy.
Companies House uses a condensed version of the full Office for National Statistics list, about 750 codes, and its guidance says to use only codes from that list or the filing may be rejected. A company must give at least one code and can give up to four if it carries out several activities.
The ONS completed a new classification, UK SIC 2026, in April 2026. As of October 2026 Companies House guidance still points filers to its condensed SIC 2007 list, so check GOV.UK for any change before relying on new codes.
Where do you find a company's SIC codes?
On the Companies House company page they appear under "Nature of business (SIC)" on the overview tab. In the free monthly register file they are in the columns SICCode.SicText_1 to SICCode.SicText_4, each holding the code and its description. The public API returns them as a sic_codes array in the company profile. SIC codes are not part of the accounts or iXBRL data.
A company sets its codes at incorporation and can change them when it files a confirmation statement.
Worked example
Example (illustrative, not a real company): a company builds accounting software and also sells implementation consulting. It could declare:
| Code | Description |
|---|---|
| 62012 | Business and domestic software development |
| 62020 | Information technology consultancy activities |
Both codes are in division 62, so in a sector analysis grouped by first code and division the company counts as computer programming and consultancy. A company that has stopped trading might instead show 99999 "Dormant Company" or 74990 "Non-trading company".
Why it matters when checking a company
The SIC code is a quick consistency test: a company invoicing you for building work but registered only as 70229 "Management consultancy activities other than financial management" deserves a question. It also lets you compare a company with its industry.
Industry patterns can be large. In our analysis of the register on 1 October 2026, companies whose first SIC code fell in division 64 (financial services, including holding companies) had the highest overdue accounts rate among large divisions at 3.1%, while legal and accounting firms (division 69) were among the most punctual at 1.2% (see the data).
You can look up a company's SIC codes and filings in seconds.
Common confusions
- SIC codes are self-declared. They describe what the company says it does, not what it has been verified to do.
- They can be out of date. A company may change activity long before it updates its codes.
- The first code is not formally the "main" one, although many data tools, ours included, group companies by the first code listed.
Sources
- GOV.UK: Standard industrial classification of economic activities (SIC)
- Companies House condensed SIC list (CSV)
- ONS: UK Standard Industrial Classification of Economic Activities
FAQ
How many SIC codes can a UK company have?
A company must give at least one SIC code and can give up to four on the Companies House register. Additional codes are useful when the company carries out several distinct activities. Codes must come from Companies House's condensed list, otherwise the filing can be rejected. Codes are set at incorporation and can be updated with a confirmation statement.
How do I change my company's SIC code?
File a confirmation statement with the new codes. You do not have to wait for the annual due date: a company can file a confirmation statement at any time, and doing so restarts its 12-month review period. The online fee is £50. Choose the codes from the Companies House condensed list to avoid rejection.
What SIC code should a dormant company use?
The Companies House condensed list includes 99999 "Dormant Company", which many dormant companies use. A company that is not dormant but does not trade, for example one that only holds investments, may use 74990 "Non-trading company" or a code describing its holding activity. The accounts, not the SIC code, determine whether a company is legally dormant.
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