SIC code (Standard Industrial Classification)
What it is
A five-digit code that classifies a UK company's main business activity. Every company must have at least one SIC code, chosen at incorporation and updated via the confirmation statement if the business changes.
Why it matters
Banks, insurers and business partners check your SIC code during due diligence. An inaccurate code — such as 'general trading' when you do software consulting — can delay bank account applications or raise compliance questions.
Common mistake
Leaving the default SIC code from incorporation if the main business activity has since changed. You can update it on the next confirmation statement — it takes seconds.
Official source
Companies House — SIC codes list ↗Disclaimer
General educational guidance only — not legal, tax, accounting, immigration, investment or financial advice. We don't guarantee the information is complete, current or suitable for your situation. Always check official sources (GOV.UK, Companies House, HMRC, the relevant professional body) and speak to a qualified professional before acting. Last reviewed: June 2026.