SIC code
The Standard Industrial Classification — the 5-digit identifier UK Companies House uses to label every company's industry. The backbone of any lender's ICP filter.
Definition
A SIC code (Standard Industrial Classification) is the 5-digit numerical identifier that UK Companies House assigns to every registered company to describe its primary economic activity. The active UK system is SIC 2007, maintained by the Office for National Statistics.
Structure
SIC 2007 is a hierarchical system with five levels:
- Section (single letter, A–U) — e.g.
F= Construction - Division (2 digits) — e.g.
41= Construction of buildings - Group (3 digits) — e.g.
412= Construction of residential and non-residential buildings - Class (4 digits) — e.g.
4120= Construction of residential and non-residential buildings - Subclass (5 digits) — e.g.
41201= Construction of commercial buildings
When working with Companies House data, you'll always see the 5-digit subclass form. A UK company may register up to four SIC codes, listed in order of significance.
Why it matters for lenders
The SIC code is the most reliable industry filter available on UK SMEs — it's official, structured, and present on essentially every registered company. UK fintech lenders typically build their ICP (ideal customer profile) on a whitelist of SIC prefixes, e.g.:
- 41–43 (Construction) — typical working-capital and equipment-finance fit
- 45–47 (Retail / wholesale / vehicle trade) — strong cash-flow fit
- 55–56 (Hospitality / food service) — high-volume merchant-cash-advance fit
- 62–63 (IT / information services) — invoice-finance fit
- 69–74, 82 (Professional services) — invoice-finance and SaaS-credit fit
Filtering raw Companies House output by an SIC whitelist is the first step in turning a 3,000/day incorporations firehose into a 100/day actionable lead list.
Limits
SIC codes are self-declared at incorporation. Some companies pick a generic code (74909 "Other professional, scientific and technical activities n.e.c.") that tells you little. Anti-pattern: relying on SIC alone — pair it with company name signals and director-context enrichment for sharper ICP matching.
Related
- Companies House — the source of SIC data
- Borrower intent data — how SIC filtering becomes a lead-gen channel
- How UK fintech lenders source SME borrowers in 2026
Frequently asked
How many SIC codes are there in the UK?
The UK SIC 2007 system contains approximately 615 active 5-digit codes, grouped into 88 divisions and 21 broad sections (A–U). A UK company can register up to four SIC codes at Companies House.
Where can I look up a UK SIC code?
The Office for National Statistics publishes the official SIC 2007 hierarchy. Borrowsignal also provides a free SIC code lookup tool that lets you search by keyword.
Are SIC codes the same as NACE or NAICS?
UK SIC 2007 is aligned to (but not identical with) the European NACE Rev. 2 classification. NAICS is the North American equivalent and is structurally different — a US NAICS code does not map cleanly to a UK SIC code.