SIC codes explained: how to use them when targeting new companies

A Standard Industrial Classification (SIC) code can narrow the daily flow of new Companies House incorporations down to a sector a practice actually serves, but it is a self-reported label the directors chose at incorporation, not a verified description of what the company does.

If you've ever looked up a company on Companies House, you've seen a SIC code, even if you didn't pay it much attention. Every limited company is assigned at least one when it incorporates, and Companies House does not check or audit the choice. For accountancy practices, SIC codes remain one of the most practical fields for filtering new companies by sector — used carefully, alongside the limitations set out below.

What SIC codes are

SIC stands for Standard Industrial Classification. It's the UK's system for categorising business activities into a structured, hierarchical code system. The current version is the 2007 SIC code framework, which is based on the European NACE Rev. 2 classification.

Every company registered at Companies House has at least one SIC code on its record. The code describes the company's primary business activity — or, more precisely, the activity the directors said the company would carry out when they incorporated it.

SIC codes are one of several data fields available from the day of incorporation. For a broader view of what's on the register, see our Companies House data guide.

How SIC codes work

SIC codes are hierarchical. They start broad and get more specific as you add digits. The structure runs from section (a single letter) down to subclass (a five-digit code):

• Section — the broadest category, identified by a letter. For example, Section M covers "Professional, Scientific and Technical Activities."
• Division — a two-digit code. Division 69, within Section M, covers "Legal and Accounting Activities."
• Group — a three-digit code. Group 69.2 narrows to "Accounting, Bookkeeping and Auditing Activities; Tax Consultancy."
• Class — a four-digit code. Class 69.20 is the specific class for accounting and auditing.
• Subclass — a five-digit code. Subclass 69201 identifies "Accounting and Auditing Activities" specifically.

Worked example: if your practice serves construction-sector clients, you'd start at Section F (Construction), look at Division 41 (Construction of Buildings), and could filter as broadly as the whole division (41) or as narrowly as subclass 41201 (Construction of Commercial Buildings). Broader codes capture more companies; narrower codes give you more precise targeting.

How they're assigned

When directors incorporate a new limited company, they choose one or more SIC codes from the Companies House condensed list — based on UK SIC 2007, but shorter than the full Office for National Statistics list — published at resources.companieshouse.gov.uk/sic/. The choice is self-reported: Companies House does not verify or audit it at the point of filing.

That distinction matters. A director incorporating a management consultancy might choose SIC code 70229 ("Management Consultancy Activities other than Financial Management"), or they might choose something more generic. There's no penalty for choosing a broad code, and no review process to check the selection. This is one of the system's practical limitations.

A company can list up to four SIC codes to describe its activities. In practice, many new companies list just one. Once filed, a code doesn't update itself — the company has to change it, and the only way to do that is on a confirmation statement (Companies House, "Keeping your Standard Industrial Classification (SIC) code accurate", 28 May 2026). Companies House names one pattern as one of the most common discrepancies it sees: an active, apparently trading company still carrying a dormant (99999, Dormant Company) or non-trading (74990, Non-trading company) code left over from incorporation. Neither code proves the company itself is dormant — it may just be a stale filing — but either is a reason to check before assuming the record reflects current activity.

SIC codes accountants should know

Companies House uses a condensed version of the standard UK SIC 2007 list — fewer entries, some with descriptions that differ slightly from the ONS original. Below is a selection commonly relevant to accountancy practices, grouped by sector. Use this as a starting point, not an exhaustive list.

Professional services: 69201 (Accounting and auditing activities), 69202 (Bookkeeping activities), 69203 (Tax consultancy), 70229 (Management consultancy activities), 74909 (Other professional, scientific and technical activities).

Construction: 41100 (Development of building projects), 41201 (Construction of commercial buildings), 41202 (Construction of domestic buildings), 43110 (Demolition), 43290 (Other construction installation).

Technology and digital: 62011 (Ready-made interactive leisure and entertainment software development), 62012 (Business and domestic software development), 62020 (Information technology consultancy activities), 62090 (Other information technology service activities).

Retail and e-commerce: 47110 (Retail sale in non-specialised stores), 47910 (Retail sale via mail order or internet).

Health and care: 86210 (General medical practice activities), 86220 (Specialist medical practice activities), 86900 (Other human health activities).

Property: 68100 (Buying and selling of own real estate), 68209 (Other letting and operating of own or leased real estate), 68310 (Real estate agencies).

The authoritative reference for codes used in company filings is the Companies House SIC code list at resources.companieshouse.gov.uk/sic/.

Using SIC codes to target new companies

SIC codes become genuinely useful when you combine them with new incorporation data. Every company that incorporates selects its SIC codes on day one, which means you can filter the daily flow of new incorporations by sector from the start.

Companies House's advanced company search accepts one SIC code per search — entering more than one, for example as a comma-separated list, returns an error (checked 17 September 2026). A selection of several codes means running one search per code and combining the results yourself. A company holding two of your matching codes will appear in both searches, so simply adding the totals together overcounts distinct companies; dedupe by company number if you need an accurate count.

The practical approach is to combine SIC code filtering with location filtering (using postcode areas) to produce a focused, relevant list. A practice in Leeds specialising in tech clients, for example, might run separate searches across SIC codes 62011 to 62090 in the LS postcode area and combine the results. The outcome is a short, manageable list of new companies that match both the sector and the geography you serve. Turning that combination into a versioned definition sized to what the practice can actually review is covered in building a new-company search profile.

SIC codes are just one of several fields available at incorporation. Paired with the registered address and company name, they give you enough context to decide whether a new company is worth reaching out to.

For a sense of how many companies each sector adds nationally, our free company statistics by industry count new incorporations across curated groups of SIC codes, and the published methodology lists the exact codes included in each group.

Limitations to be aware of

SIC codes are useful, but they're not perfect. Being honest about the limitations helps you use them more effectively.

Self-selected, not verified. Directors choose their own SIC codes at incorporation. Some choose carefully; others pick the first code that looks roughly right. There's no review process and no consequence for choosing a generic code.

Generic codes are common. SIC code 82990 ("Other Business Support Service Activities Not Elsewhere Classified") is a catch-all that a wide range of companies end up under. If your target sector is specific, you'll occasionally miss companies that chose a vague code, and occasionally pick up companies that don't quite fit.

Activities evolve. A company's SIC code reflects what the directors intended at incorporation. If the business pivots, the SIC code may not be updated. For established companies, the code can be out of date. For new companies, it's usually a reasonable indicator.

The practical takeaway: treat SIC codes as a useful starting filter, not a guarantee. Combine them with location filtering and a quick review of each company name, and you'll have a reliable enough shortlist to work from.

Frequently asked questions

Can a company have more than one SIC code?

Yes. A company can list up to four SIC codes. In practice, many new companies list just one. Multiple codes are more common when a company operates across distinct sectors.

How do I find the right SIC codes for my targeting?

Start with the broad division (two-digit code) for your target sector, then narrow to specific groups or classes as needed. The lists earlier in this guide cover the most common codes for accountant targeting.

Are SIC codes always accurate?

Not always. Because they're self-selected, directors sometimes choose a generic code or one that doesn't precisely match their activity, and the code isn't updated unless the company files a confirmation statement that changes it. A common example is an active company still showing a dormant (99999) or non-trading (74990) code left over from incorporation. Treat SIC codes as a useful starting filter, not the sole criterion for your targeting.

How Launch Register can help

Once you have chosen a defensible set of SIC codes, Launch Register can apply them alongside location preferences to narrow new incorporations for review. The codes remain a screening input: you still decide whether each company fits your practice.