Reference

Companies House can now challenge an inaccurate SIC code

A wrong SIC code used to be a harmless piece of admin nobody ever revisited. Since the Economic Crime and Corporate Transparency Act (ECCTA) gave Companies House stronger powers to challenge, reject or remove inaccurate register information, a stale or mismatched code is a live compliance point, not just a lender-misreading problem.

See complex or misunderstood industries

Recognition

"It's just a code, nobody looks at it" stopped being true

Most businesses pick a SIC code once, at incorporation, and never think about it again. For years that was reasonable: Companies House accepted what was filed with limited verification, and the code sat quietly in the background. ECCTA changes that. Companies House now actively polices the register for accuracy, and a SIC code is one of the specific data points it's named as a focus.

What actually changed

New powers to challenge, reject or remove, not a new code list

It's worth being precise about what did and didn't change. As of Companies House's own guidance (Keeping your SIC code accurate, 28 May 2026), it has not replaced the SIC classification system itself with a new "SIC 2026" list, whatever some third-party guides currently imply. Replying to readers under that post in June 2026, Companies House said a future framework remains under discussion with the ONS and has not been agreed or implemented. What ECCTA actually did was give Companies House stronger legal powers to challenge, reject or remove information on the register, including SIC codes, that looks incorrect, inconsistent or misleading. That's an enforcement change, not a reclassification.

The specific pattern Companies House has called out: a dormant or non-trading SIC code left in place on a company that's actually trading. If that describes your filing, it's worth updating before it gets flagged rather than after.

Why this matters here specifically

Misclassification was already a lending problem

Lenders and funding bodies use SIC codes when they assess eligibility, so a code that says dormant, or says very little about what the company does, can complicate an application before anyone has read the accounts.

Under ECCTA the same code is now also a register-accuracy question in its own right. An inaccurate code is worth correcting for both reasons.

Decision helper

Your SIC code situationWhat to doNot this

Dormant/non-trading code, company is actually active→Update it on the next confirmation statement, don't wait→Assuming an old code is harmless because nobody's queried it yet

"Not elsewhere classified" or a broad, generic code→Check whether a more specific, currently-available code fits better→Leaving it vague because "it's close enough"

Accurate code, but a lender still misreads the business→The code isn't the problem: see the specific industry pages this site covers→Assuming a code change alone fixes a facility-fit problem

Alternatives and limitations

If the code is wrong, fix the code

An incorrect code is a filing problem, and the fix is on your next confirmation statement. If the code is right and a lender still misunderstands the business, that is a different problem, and changing the code won't solve it. Complex or Misunderstood Industries covers the sectors where that happens most, and why.

Code right, but a lender still misreads the business?

Tell us what the business actually does and what you're trying to arrange.

Tell us what's happening → See the sectors lenders most often misread

Adam Parker

Founder of Muswell Rose Consulting Ltd, which trades as Established Finance · former Managing Director of Penny, an invoice finance business, with 15+ years across mortgages, commercial finance and fintech lending.

Last updated: 16 September 2026

Common questions

Questions about this

Has Companies House introduced a new SIC 2026 classification list?

Not yet, as far as this page can verify. A future SIC framework has been under discussion between Companies House and the ONS, but Companies House said in June 2026, replying to readers under its own SIC guidance post, that no final new framework has been agreed or implemented. What has genuinely changed is enforcement, not the classification list itself: Companies House now has stronger legal powers under ECCTA to challenge, reject or remove information on the register, including SIC codes, that appears incorrect, inconsistent or misleading.

What SIC code mistake does Companies House flag most often?

Using a dormant or non-trading code on a company that is actually trading. Companies House has specifically named this as one of the discrepancies most likely to attract scrutiny under its new powers.

Can a wrong SIC code actually affect a finance application?

Yes, in practice it already could before ECCTA, and the risk is higher now. Lenders and funding bodies use SIC codes to assess eligibility, and a mismatch between the code on the register and what the business actually does can be enough on its own to cause delays or complications in an application, independent of the business's actual creditworthiness.