UK Standard Industrial Classification (SIC) Code Explained

Last updated: July 2, 2026 4 min read

You need to provide at least one UK Standard Industrial Classification (SIC) code to Companies House during company formation. The government uses the code as a statistical tool to classify economic activities and track trends, while banks, mortgage lenders, and HMRC use it to assess your business.

Standard Industrial Classification code diagram with certification, compliance, and industry classification icons

Written by: Robert Engeham

Managing Director, Your Company Formations

Key Highlights

The wrong code leads to rejection of mortgage or business loan applications.
HMRC uses your SIC code to risk-profile R&D tax credit claims.
For buy-to-let property, use code 68209; using 68100 can block mortgages.
Online retailers must use code 47910 to avoid issues with payment providers.
You can only change your SIC code by filing a Confirmation Statement (CS01).

How to Choose the Right SIC Code for Your Business

Your first SIC code describes the nature of your business by detailing your main revenue-generating activity. You can add up to three more codes to represent other significant business activities. The process is straightforward, but the details matter, especially in a regulated industry.

Step 1: Search the Official Companies House Condensed List

Start with the Companies House condensed SIC code list at resources.companieshouse.gov.uk/sic/. Companies House uses a condensed version of the full Office for National Statistics (ONS) SIC 2007 framework, and not every ONS code appears on it. Entering a code that exists in the ONS list but not the Companies House condensed SIC code list will result in a rejected filing.

To search the sic code list:

Use keywords related to your main business activity.
If you cannot find a match, search the public register for similar companies to see which classification code they use.

Step 2: Select the Most Specific Code Available

Avoid general, catch-all codes where a more precise option exists. For example, instead of using 74990 (“Non-trading company”) or 82990 (“Other business support service activities not elsewhere classified”), find the code with a description that accurately reflects your trade.

Step 3: Use the Correct Code for High-Stakes Industries

For certain business types, selecting the correct Standard Industrial Classification of Economic Activities is critical to securing financing or passing verification checks.

Buy-to-Let (BTL) Property Companies: Use code 68209 (Other letting and operating of own or leased real estate). Most BTL mortgage lenders require this exact code.
Property Developers (Flipping): Use code 68100 (Buying and selling of own real estate). Do not use this for a BTL rental portfolio.
E-commerce and Online Retail: Use code 47910 (Retail sales via mail-order houses or via the Internet). This is the correct code for businesses using Shopify, Amazon, or eBay.
IT Contractors and Consultants: Use code 62020 (Information technology consultancy activities).
Software Developers: Use code 62012 (Business and domestic software development).
Management Consultants: Use code 70229 (Management consultancy activities other than financial management).
Holding Companies: Use code 64209 (Activities of other holding companies n.e.c.).

The Financial Consequences of Using the Wrong SIC Code

While Companies House does not issue fines for an incorrect SIC code, other organisations use them to make critical financial decisions about your company. Failing to select an appropriate code can have significant and costly consequences.

Your BTL Mortgage Application Can Be Rejected

Most buy-to-let mortgage lenders will automatically reject applications from limited companies that do not use SIC code 68209. Lenders view code 68100 (‘Buying and selling of own real estate’) as a property-trading activity, which carries a higher risk profile than a company holding property for rental income.

HMRC Will Scrutinise Your R&D Tax Credit Claim

HMRC uses your SIC code to risk-profile R&D tax credit claims. A claim from a software company with a software development code (e.g., 62012) is expected. However, a claim from a company with a code for a non-technical industry, such as ‘Retail’ or ‘Catering’, is a red flag that triggers an immediate, detailed compliance check, often leading to claim rejection.

Payment Providers Can Flag Your Account

Payment gateways like Shopify Payments and Stripe verify your business activity during onboarding. An online retailer using a physical retail code (e.g., 47710 for a clothing store) instead of the correct e-commerce code (47910) can cause your account to be flagged for review, potentially delaying your ability to accept payments.

Banks May Refuse to Open a Business Account

During due diligence, banks assess the risk associated with your industry. A SIC code for a high-risk sector (e.g., cryptocurrency, gambling) or a vague, non-descriptive code can lead to a business bank account application being rejected.

How to Change or Update Your SIC Code with Companies House

You can only change your company’s SIC code by filing a Confirmation Statement (form CS01). There is no separate form for this purpose.

File a Confirmation Statement
You can file a confirmation statement online for £50 or by post for £110.
Wait for your due date or file early
If the change is urgent, you can file a confirmation statement early. You will not have to file again for another 12 months.
Add or remove codes
On the form, update your record by entering the new code(s) you wish to add and listing any old codes that no longer apply.

Frequently Asked Questions About SIC Codes

Do SIC codes restrict your business activities?

A SIC code is a statistical descriptor for Companies House and the ONS, used to produce statistical data. It carries no legal weight and does not restrict your company from performing any lawful business activity, even if it falls outside the description of your registered code.

How many SIC codes can I have?

You can provide up to four SIC codes. While one SIC code often suffices to capture a company’s primary activity, more complex or multi-faceted businesses may benefit from selecting up to four codes to better reflect their needs. The first one listed should represent your company’s main business activity.

What SIC code should I use for a dormant company?

Use code 99999 for a dormant company. This code signals to anyone viewing the public register that the company is dormant and has had no significant accounting transactions. If the company begins trading, you must update the code on your next Confirmation Statement.

What is the difference between a dormant and a non-trading company?

A dormant company (99999) is one that has previously traded but is not currently trading, or has been formed but has never traded. A non-trading company (74990) is typically a newly formed establishment that has not yet commenced any business activities.

Do I need a SIC code to register a limited liability partnership?

Unlike companies, limited liability partnerships (LLPs) are not subject to the SIC code requirement. This exemption applies both at the formation stage and throughout the LLP’s lifecycle, eliminating the need to choose or update codes on confirmation statements.

Article byRobert Engeham

Robert Engeham is Founder and CEO of Your Company Formations and an expert in UK company formation, Companies House compliance and business startups. Having worked with thousands of entrepreneurs from the UK and overseas, Robert regularly provides commentary on entrepreneurship, regulatory reform, corporate governance and the practical challenges facing growing businesses. His work focuses on making complex business topics easier to understand while helping founders build stronger businesses from day one.