What is a UK SIC 2007 code?

A UK SIC 2007 code is a five-digit number assigned by the Office for National Statistics to classify the economic activity of a business. Every company registered at Companies House must declare at least one SIC code on its confirmation statement. The codes run from 00100 (growing of rice) to 99000 (activities of extraterritorial organisations) and are grouped into 21 top-level sections labelled A to U.

How many SIC codes can a company have at Companies House?

Companies House allows up to four SIC codes per registered company. The first code is the primary activity. Directors can add secondary codes to reflect diversified operations, which means a firm providing both recruitment services (78200) and HR consulting (70210) would carry both codes. For targeting purposes, filtering on a secondary code can uncover companies your competitors miss.

What is the difference between SIC 2007 and the older SIC 2003?

SIC 2003 had 17 sections and used a four-digit structure for its base codes. SIC 2007 expanded to 21 sections (A to U) and uses five-digit codes, adding finer granularity across technology, professional services, and information industries. Companies House mandated the switch in 2009. Any data file still using SIC 2003 codes is at least 17 years out of date and should be treated with caution.

How accurate are Companies House SIC codes for B2B targeting?

Accuracy varies by sector. Larger companies in regulated industries (financial services, construction, healthcare) tend to declare codes precisely. Many SMEs and micro-businesses self-assign codes and sometimes choose the nearest match rather than the most accurate one. Technology companies are a known pain point: a cloud software firm might sit under 62020 (IT consultancy) rather than 62012 (business and domestic software development). Combining SIC codes with job-title filtering and firmographic signals improves precision considerably.

How do UK SIC 2007 codes map to US NAICS codes?

There is no official direct crosswalk between UK SIC 2007 and the North American Industry Classification System (NAICS). The ONS publishes a correspondence table between SIC 2007 and NACE Rev.2 (the EU standard), and the US Census Bureau maintains a NAICS-to-NACE mapping. A UK-to-NAICS conversion therefore involves a two-step table join via NACE. For a UK-only data file, NAICS codes are irrelevant; SIC 2007 is the operative classification.

Can I build a B2B target list using SIC codes alone?

SIC codes give you the industry backbone, but a complete targeting brief adds at least two further filters: employee band or turnover band (to size the organisation) and geography (by region, county, or postcode). For decision-maker outreach you also need job function and seniority. A brief that says 'SIC 62 plus 50-249 employees plus South East England' will return a much cleaner, more actionable file than SIC codes alone.

UK SIC 2007 codes explained for B2B targeting

What is SIC 2007 and who maintains it?

The Standard Industrial Classification for the United Kingdom, 2007 edition, is the official system for grouping businesses by their primary economic activity. The Office for National Statistics (ONS) owns and maintains it, and the framework aligns to NACE Rev.2, the European Union's equivalent classification. That alignment matters for comparative statistics but has no bearing on day-to-day UK targeting, where SIC 2007 is the operative standard.

Every company registered at Companies House must declare at least one SIC code on its annual confirmation statement (previously the annual return). The requirement was formalised when Companies House adopted SIC 2007 in October 2009. Before that date, older filings used SIC 2003 or, in some cases, SIC 1992. If you are working with a data file that carries the older four-digit codes, the supplier is drawing on outdated records.

The ONS publishes the full SIC 2007 index on its website, cross-referencing the five-digit code against the written description and, for common trades, against informal business-type names. The ONS SIC 2007 structure page is the authoritative reference; you can also look up individual company codes through the Companies House public register.

How is SIC 2007 structured?

The classification uses a five-level hierarchy. Understanding each level changes how you use SIC codes in targeting.

Level	Label	Format	Count	Example
1	Section	Single letter A-U	21	J: Information and communication
2	Division	Two digits	88	62: Computer programming, consultancy
3	Group	Three digits	272	620: Computer programming, consultancy
4	Class	Four digits	615	6201: Computer programming activities
5	Subclass	Five digits	731 (in UK SIC)	62012: Business and domestic software development

The fifth digit is purely UK-specific. Where the international ISIC Rev.4 classification stops at four digits, the ONS added subclasses to reflect distinctions that matter in the UK economy. A classic example is the split within Division 62 between bespoke software development (62012), business software publishing (62021), and IT consultancy (62020). All three would appear under a blunt "computer sector" filter, but they represent very different buyer profiles.

The 21 sections at a glance

Sections form the broadest targeting layer. Most B2B campaigns operate within three or four sections. The full list runs from Section A (Agriculture, Forestry and Fishing) through Section U (Activities of Extraterritorial Organisations and Bodies). The sections most frequently used in UK B2B prospecting are:

C: Manufacturing (divisions 10 to 33, covering food production through fabricated metal products to medical equipment)
F: Construction (divisions 41 to 43)
G: Wholesale and Retail Trade (divisions 45 to 47)
J: Information and Communication (divisions 58 to 63, the home of most technology businesses)
K: Financial and Insurance Activities (divisions 64 to 66)
L: Real Estate Activities (division 68)
M: Professional, Scientific and Technical Activities (divisions 69 to 75, covering solicitors, accountants, architects, management consultants, and marketing agencies)
N: Administrative and Support Service Activities (divisions 77 to 82, including recruitment, facilities management, and travel agents)

How SIC 2007 differs from SIC 2003

SIC 2003 used 17 sections (A to Q) and its base classification topped out at four digits. The 2007 revision expanded to 21 sections, adding Sections S (Other Service Activities), T (Activities of Households as Employers), and U (Extraterritorial Organisations) as distinct groupings. Critically, it restructured the technology and professional-services landscape: what SIC 2003 lumped under Division 72 (Computer and Related Activities) became multiple divisions under Section J in 2007, allowing meaningful differentiation between software publishers, IT consultancies, and data-processing services.

From a data-buyer's perspective, the practical implication is this: any B2B list originally compiled under SIC 2003 codes cannot be directly cross-walked to 2007 codes without manual mapping. If a supplier quotes SIC codes without specifying the edition, ask. The gap matters most in fast-moving sectors like technology and professional services where the two systems categorise businesses very differently.

How Companies House captures SIC codes

When a company incorporates, the director completing the application picks SIC codes from a dropdown on the Companies House online form. The same codes are confirmed (or updated) on each annual confirmation statement. There is no external verification step: Companies House accepts whichever codes the director selects. A newly formed fintech startup could legitimately register under 64999 (Other Financial Service Activities Not Elsewhere Classified) or under 62012 (Business and Domestic Software Development), depending on how its director views the primary business.

Companies can carry up to four SIC codes simultaneously. The first is the primary activity. The others reflect secondary or ancillary activities. A staffing firm that also provides HR software might sit under 78200 (Temporary Employment Agency Activities) as its primary code and 62021 (Business and Domestic Software Publishing) as a secondary. A targeting query filtering for SIC 78200 would find it. A query for SIC 62021 would also find it, probably in combination with pure software publishers.

Known accuracy gaps

Three categories of companies consistently have imprecise SIC codes: recently incorporated businesses (directors pick a plausible code quickly and rarely update it), micro-businesses with fewer than five employees (less regulatory scrutiny encourages loose self-classification), and diversified holding companies (they often carry a generic code like 64202, Activities of Other Holding Companies). For these segments, supplement SIC filtering with job-title keywords, website content signals, or manual review of shortlists.

Targeting techniques: how to use SIC codes well

Broad section targeting for volume campaigns

When you need scale and the product or service is genuinely relevant to an entire sector, filtering at the section or division level gives you volume without excessive fragmentation. A supplier of industrial safety equipment targeting all of Section C (Manufacturing) or all of Division 41-43 (Construction) is applying a reasonable broad brush. At this level, the job is done by refining other dimensions: employee count of 50 or more, turnover above £2 million, specific counties or regions.

Five-digit precision for niche campaigns

The five-digit subclass is where experienced B2B data buyers operate when the offer is specialist. A legal technology firm targeting only solicitors and barristers' chambers uses codes 69101 (Barristers at Law) and 69102 (Solicitors). Mixing them with management consultants (70210) would add noise. A manufacturer of dental consumables targets 86230 (Dental Practice Activities) rather than the whole of Section Q (Human Health and Social Work Activities).

Multi-code combination targeting

Because Companies House allows up to four SIC codes per company, a targeting brief can include a list of acceptable codes rather than a single one. A cybersecurity consultancy might sensibly target any company where at least one SIC code falls within the range 62011 to 63990 (the information and communication technology subclasses), on the basis that IT-intensive businesses are the relevant buyer universe regardless of whether IT is their primary or secondary activity.

In our experience, multi-code combination queries return 15 to 25 per cent more qualifying records than single-code queries in the technology and professional-services sectors, precisely because so many companies in those spaces carry a second code that reflects a commercial activity distinct from their registered primary classification.

Excluding non-trading entities

SIC codes include several classes that identify dormant or holding structures rather than active trading companies. Code 64202 (Activities of Other Holding Companies) and 70100 (Activities of Head Offices) are the most common culprits. A well-built data file suppresses these by default, but if you are building your own filter from raw Companies House data, exclude them explicitly. Dormant companies have no procurement budget and no decision-makers to reach.

Building a targeting brief: a worked example

A Bristol-based software firm wants to sell a fleet management platform to logistics and distribution operators across England and Wales with 50 to 500 employees. Here is how a SIC-based targeting brief would come together.

Step 1: identify the relevant SIC codes. The primary targets are in Division 49 (Land Transport and Transport via Pipelines) and Division 52 (Warehousing and Support Activities for Transportation). Relevant five-digit codes include 49410 (Freight Transport by Road), 52100 (Warehousing and Storage), 52290 (Other Supporting Transport Activities), and 45200 (Maintenance and Repair of Motor Vehicles) for fleet-adjacent businesses.

Step 2: set firmographic filters. Employee band 50 to 500 removes micro-firms (too small to justify enterprise software) and the largest national carriers (who have in-house IT teams and long procurement cycles). Turnover above £2 million as a secondary check.

Step 3: set geography. England and Wales by registered office postcode. The client does not cover Scotland or Northern Ireland. Within England and Wales, prioritise the Midlands and South West where the client has existing sales resource.

Step 4: exclude holding companies. Suppress SIC 64202 and 70100 to avoid mailing group head-office shells.

Step 5: add decision-maker job function. SIC codes define the company universe; they say nothing about who to contact. Layer on job titles: Fleet Manager, Logistics Director, Operations Director, Head of Transport. That combination delivers a file of named individuals at qualifying companies, not just a company list.

The result for this brief would typically return 4,000 to 8,000 qualifying companies across England and Wales, yielding several thousand contactable decision-makers depending on company size distribution within the target bands. When building the lawful basis for outreach, the data in our B2B file is compiled under legitimate interests from public sources; buyers should complete a Legitimate Interests Assessment before running a campaign of this type.

Crossing SIC 2007 to NAICS: what the mapping looks like

North American Industry Classification System (NAICS) codes are used in the United States, Canada, and Mexico. UK B2B targeting does not use them, but multinational clients sometimes ask whether a UK SIC code corresponds to a given NAICS code for reporting or segmentation purposes.

There is no direct, official UK SIC 2007-to-NAICS mapping. The route is indirect: the ONS publishes a correspondence between SIC 2007 and NACE Rev.2; the US Census Bureau publishes a correspondence between NAICS and NACE. Joining those two tables gives an approximate bridge, but the match is many-to-many in both directions. A single NAICS code often spans two or three SIC classes, and vice versa.

Classification system	Used in	Structure	Maintained by
SIC 2007	UK	5 digits, 21 sections	ONS
NACE Rev.2	European Union	4 digits, 21 sections	Eurostat
NAICS 2022	US, Canada, Mexico	6 digits, 20 sectors	US Census Bureau / Statistics Canada
ISIC Rev.4	International (UN)	4 digits, 21 sections	UN Statistics Division

For a UK-only data file, NAICS is irrelevant operationally. SIC 2007 is the classification every UK record carries, and it is the one you filter on. If you are a US parent company asking a UK data supplier to provide records in a NAICS format, the correct answer is that the UK file uses SIC codes; any NAICS translation is an approximate post-processing step, not a native attribute of the data.

Practical limits and how to compensate

SIC codes are self-declared and rarely updated mid-company-life. A digital marketing agency formed in 2012 might still carry 73110 (Advertising Agencies) even though it now derives 80 per cent of its revenue from SaaS platform sales. The company's website, LinkedIn profile, and job postings tell a more accurate story than its Companies House registration.

Three compensation strategies work well in practice. First, pair SIC targeting with job-title keyword filtering: "Head of Growth" at a company coded 73110 is a stronger intent signal than the SIC code alone. Second, use SIC codes to set the initial universe, then apply a manual or AI-assisted review to the top 500 records before investing in full campaign volume. Third, consider choosing a B2B data provider that supplements Companies House SIC codes with independently verified activity data, so the primary classification is not the only industry signal in the record.

The underlying accuracy problem is a feature of public registration systems everywhere, not a flaw specific to Companies House. US businesses self-report NAICS codes to the Small Business Administration with similar imprecision. The SIC system is still the best single-field industry indicator available in UK B2B data because it covers the entire registered-company universe, not just firms that have opted into a particular directory or platform.