Changing SIC Codes: A Complete Guide for UK Companies

Every UK company registered with Companies House is assigned one or more Standard Industrial Classification (SIC) codes to describe the nature of its business activities. While many founders choose their SIC codes during incorporation and rarely think about them again, businesses often evolve.

A software startup may begin offering consultancy, an online retailer might launch manufacturing, or a marketing agency could expand into training services.
When your business activities change, your SIC codes should reflect that change.
This guide explains what SIC codes are, when you should update them, how to change them, and why keeping them accurate is an important part of maintaining a compliant UK company.

What Are SIC Codes?

A Standard Industrial Classification (SIC) code is a five-digit number used by Companies House to classify the primary activities of a UK business.
Each code represents a specific industry or type of commercial activity.
For example:

• 62012 – Business and domestic software development
• 47910 – Retail sale via mail order houses or via the internet
• 70229 – Management consultancy activities
• 73110 – Advertising agencies
• 62020 – Information technology consultancy activities

Companies House uses SIC codes to:

• Categorise registered businesses
• Produce economic and statistical reports
• Help regulators understand business activities
• Improve public company records

Although SIC codes do not determine how your business is taxed, licensed, or regulated, they form an important part of your company's official record.

Why SIC Codes Matter

Many directors assume SIC codes are merely administrative details.
In reality, accurate SIC codes benefit both your company and third parties who interact with it. Correct SIC codes can help:

• Investors understand your business
• Banks assess your activities
• Suppliers perform due diligence
• Customers verify your company
• Government agencies compile industry statistics

An incorrect code rarely creates immediate legal problems, but consistently inaccurate information can create confusion and undermine credibility.

When Should You Change Your SIC Codes?

You should update your SIC codes whenever your company's principal business activities change. Common examples include:

You Enter a New Industry

A company originally providing IT consulting begins developing SaaS products. Its activities have changed significantly and should be reflected in its SIC codes.

You Stop a Previous Business Activity

A retailer permanently stops selling physical products and becomes a digital education business. The old retail SIC code may no longer be appropriate.

Your Business Model Evolves

Many startups pivot. For example:

• Digital agency $\rightarrow$ Software company
• E-commerce store $\rightarrow$ Product manufacturer
• Consultancy $\rightarrow$ Recruitment firm

Your SIC codes should evolve alongside your business.

Your Original Codes Were Incorrect

Sometimes founders simply select the wrong code during incorporation.Companies House allows corrections through future filings.

Do You Have to Update SIC Codes Immediately?

Unlike director appointments or registered office changes, there is no separate Companies House form solely for changing SIC codes. Instead, SIC codes are usually updated when filing your company's annual Confirmation Statement.
This makes the process simple. When preparing the Confirmation Statement, you can review the existing SIC codes and replace or amend them before submission.

How Many SIC Codes Can a Company Have?

A UK company can register up to four SIC codes. This is useful if your business carries out several distinct activities. For example, an online technology company might use:

• Software development
• IT consultancy
• Data processing
• Online education

The codes should represent genuine business activities rather than every possible future service.

Choosing the Right SIC Code

Finding the most suitable code is usually straightforward. Start by identifying your company's main source of revenue. Ask questions such as:

• What products do we sell?
• What services generate most income?
• What would a customer describe us as?
• Which activity occupies most of our resources?

Choose the code that best matches your actual operations—not your ambitions five years from now.

If No Code Matches Perfectly

Modern businesses often combine several services. For example, an AI startup may offer:

• Software
• Consulting
• Training
• Research

No single SIC code covers every aspect. In these situations:

• Choose the closest available code
• Use additional codes if necessary
• Focus on your principal commercial activities

Companies House understands that businesses evolve faster than classification systems.

How to Change Your SIC Codes

Updating SIC codes is relatively simple.

Step 1: Review Current Business Activities

List everything your company currently does. Ignore activities you no longer perform.

Step 2: Find Appropriate SIC Codes

Search the official SIC code list published by Companies House. Identify the codes that most accurately describe your operations.

Step 3: File Your Confirmation Statement

During the Confirmation Statement process, review your company information. Replace or amend the SIC codes where necessary.

Step 4: Submit the Filing

Once accepted, Companies House updates the public company record. The new codes become part of your official company profile.

Examples of When Companies Change SIC Codes

Example 1: Startup Pivot

• Originally: 62020 – Information technology consultancy
• Later: 62012 – Business software development

The business moved from consulting to building software products.

Example 2: E-commerce Expansion

• Originally: 47910 – Online retail
• Later added: 32990 – Manufacturing activities

The company now designs and manufactures its own products.

Example 3: Marketing Agency

• Originally: 73110 – Advertising agencies
• Later added: 70229 – Management consultancy

The company now provides strategic business consulting alongside advertising.

Can Changing SIC Codes Affect Tax?

Generally, no. Changing a SIC code does not automatically change:

• Corporation Tax
• VAT obligations
• PAYE responsibilities
• Companies House filing requirements

However, your underlying business activities may create new tax or regulatory obligations independently of the SIC code. For example: A company moving into financial services may require regulatory approval regardless of which SIC code it selects.

Do Banks and Investors Look at SIC Codes?

Sometimes. Banks, investors, lenders, procurement teams, and business partners often review Companies House records during due diligence. If your SIC code says "Retail" but your website shows "Cybersecurity software", it may raise unnecessary questions. Accurate public records help present a professional and transparent business.

Common Mistakes to Avoid

• Choosing the Broadest Possible Code: Selecting an overly generic code may not accurately reflect your activities. Choose the closest specific classification instead.
• Using Outdated Activities: If your company stopped providing a service years ago, remove the corresponding SIC code.
• Selecting Future Business Plans: Only choose codes that represent activities you currently undertake. Future expansion can be reflected later.
• Ignoring Multiple Activities: If your business genuinely operates across several sectors, use multiple SIC codes rather than forcing everything into one category.
• Forgetting to Review Codes Annually: Business models change gradually. Review your SIC codes each year before filing your Confirmation Statement.

How SIC Codes Affect Global Founders

Many overseas entrepreneurs establish UK companies before expanding internationally. Over time, these businesses often diversify. For example:

• Amazon seller $\rightarrow$ Brand owner
• Freelancer $\rightarrow$ Agency
• Consultant $\rightarrow$ SaaS company
• Importer $\rightarrow$ Manufacturer

As these changes occur, updating SIC codes helps ensure the Companies House record reflects the company's actual commercial activities. Platforms such as IncorpUK, which assist global founders with UK company formation and ongoing compliance, often encourage directors to review company information during annual filings to keep public records accurate.

Best Practices for Maintaining Accurate SIC Codes

A simple annual review can prevent outdated company records.
Use this checklist:

• [ ] Review current business activities.
• [ ] Compare them with existing SIC codes.
• [ ] Remove codes that no longer apply.
• [ ] Add new codes where appropriate.
• [ ] Ensure your website and public company profile broadly align.
• [ ] Update the codes when filing your Confirmation Statement.

Taking a few minutes each year helps maintain accurate corporate records.

Frequently Asked Questions

What does SIC stand for?

SIC stands for Standard Industrial Classification. It is a system used to categorise businesses according to their economic activities.

Can I change my SIC code after incorporation?

Yes. SIC codes can be updated through your company's Confirmation Statement whenever your business activities change.

How many SIC codes can a UK company have?

A company can register up to four SIC codes with Companies House.

Is changing a SIC code free?

There is no separate fee for changing SIC codes. Changes are typically made as part of filing your annual Confirmation Statement, which has its own filing fee.

Does changing a SIC code affect Corporation Tax?

No. A SIC code is descriptive rather than tax-determining. Your tax obligations depend on your business activities and applicable tax laws.

Can two companies use the same SIC code?

Yes. Thousands of companies may use the same SIC code if they operate in the same industry.

What if my business fits several industries?

You can register up to four SIC codes to reflect your principal business activities.

Can I leave my old SIC code if I no longer use it?

It's better to remove codes that no longer represent your business. Accurate company records improve transparency and reduce confusion.

Conclusion

SIC codes may seem like a minor administrative detail, but they play an important role in keeping your company's public profile accurate and up to date. As your business grows, pivots, or diversifies, your registered business activities should evolve as well. Fortunately, updating SIC codes is straightforward. By reviewing your operations each year and making any necessary changes when filing your Confirmation Statement, you can ensure your Companies House record accurately reflects your business today not the business you started with years ago.

For founders, particularly those managing UK companies from overseas, maintaining accurate SIC codes is one small but valuable part of broader corporate compliance. Combined with timely filings, accurate registers, and up-to-date company information, it helps build a trustworthy and well-managed business.