How to Change Your SIC Code at Companies House (Property Company Guide)

A SIC code can be changed at any time, and the change is made through the confirmation statement rather than through any dedicated form or application. If your company's confirmation statement fee has already been paid for the current twelve-month payment period, filing an updating statement purely to correct the codes costs nothing further. This page covers the mechanics of making that change for a property company: how to file it, what it costs, adding a code rather than replacing one, when to do it, and what appears on the public register afterwards.

Most property companies that need this filing were never misclassified deliberately. The codes are chosen in a few seconds during incorporation, often by a formation agent picking a plausible general option from a long list, and nobody looks at them again until a lender does. A company set up to hold and let flats can end up on the register describing itself as a dealer or a general trading business, and the record then quietly says the wrong thing for years. Before filing anything, settle what the codes should actually read: our guide to the SIC code for an SPV property company sets out which classifications buy-to-let lenders accept and which one causes declines.

How to change your SIC code

The standard industrial classification is a short numeric label recorded against your company at Companies House to describe what the business does. It is set for the first time when the company is incorporated, on the application to register, which is why the codes on an older company often reflect whatever the formation agent selected at the time rather than what the company does now. Our guide to setting up a property investment company covers that first-time selection.

To change it afterwards you file a confirmation statement, form CS01. There is no CS01 variant for SIC codes, no separate application, and nothing to post unless you choose to file on paper. The confirmation statement is the annual filing in which a company confirms that the information Companies House holds about it is correct, and the classification is one of the items you are asked to confirm. Where the codes shown are wrong, you correct them at that step, and the corrected codes are what the statement then confirms.

Two routes exist, and they differ only in timing.

Route	When you file	What it costs	Use it when
At annual renewal	On or before the confirmation statement due date	The £50 fee (online) that was due anyway	There is no deadline pressure and the next statement is close
Updating statement	Any time you choose, mid-period	Nothing further if the period's fee is already paid	You need the register corrected now, typically before a lender looks at it

The second route is the one most property company directors want and the one most of them do not know exists. A confirmation statement is not restricted to the due date. You may file one whenever you want the register brought up to date, and filing early simply resets the next due date to twelve months from the statement date. That is how a code gets corrected in a working day rather than in nine months' time.

The filing itself is done through the Companies House online service using the company's authentication code, and the modern confirmation statement also carries the newer items introduced for all companies from March 2024, a registered email address and a statement of lawful purposes. If yours have not been supplied yet, the service will collect them in the same session. A confirmation statement filing is also the natural moment to check the registered office address shown for the company, since that record is confirmed at the same time.

Does changing your SIC code cost anything

No fee attaches to the change itself. What carries a fee is the confirmation statement, and the current Companies House rates are £50 filed online or by software and £110 filed on paper. That fee applies once with the first statement in each twelve-month payment period, which is the wording that makes the position on a second statement clear: an updating confirmation statement filed inside a period you have already paid for carries no further charge.

The distinction matters because the £50 is often misread as the price of the change. It is not. It is the annual filing fee, due whether or not a single detail on the register alters, and a company that never changes anything still pays it. The published rates sit on the Companies House fees page on gov.uk.

It is worth contrasting this with a company name change, which people often assume works the same way. A name change is a separate filing on a separate form and it does cost money in its own right, currently £20 online, £30 on paper and £85 for the same-day service. So a director doing both jobs in one sitting pays for the name change and, if the period's confirmation statement fee is already settled, nothing for the classification change.

Adding a code versus replacing one

A company can hold up to four SIC codes on the register at the same time, and adding one does not require removing another. This is the part that trips people up, because the question is usually asked as "can I add another code" when the underlying problem is that an existing code is wrong.

The two are not interchangeable. Adding is right where the company has genuinely taken on an additional activity and the existing code still describes something it does. A company that has always held and let residential property and has now started managing property for a third party has two real activities, and the register should show both. Replacing is right where a code describes something the company does not do at all, which is the common case for a property company incorporated by a formation agent under a general trading classification, or under a dealing classification when the business is a hold-and-let one.

The reason the distinction has commercial consequences is that a lender reads every code listed, not just the first. Leaving a genuinely wrong code on the record alongside a correct one does not neutralise it. The underwriter sees an activity the company says it carries on, and where that activity reads as trading or dealing rather than investment, several buy-to-let lenders decline before the case reaches valuation. That mechanic, and which codes trigger it, is set out on the SIC code guide for property companies.

Situation	Add or replace	Why
Company started a second, genuine activity	Add	Both descriptions are true, and the register may hold up to four
Formation agent recorded a generic trading code	Replace	The activity was never carried on, so it should not stay on the record
Company registered for dealing but only ever lets	Replace	The wrong code is read by lenders as what the company does
Company will both hold and develop	Add the second, keep the first	Both activities are real, so the record should show both

Does the SIC code affect tax

No. The classification is a statistical device. It exists so that company activity can be counted consistently for national statistics and so that anyone searching the register can see at a glance what a company is for. It is not a tax status, it is not an entry on the CT600 corporation tax return, it does not appear as a determinant in the corporation tax computation, and HMRC does not consult the Companies House classification to decide how a company's profits are taxed. Profits are taxed according to what the company actually did, established from its accounts and its return, and a company that records a letting classification but in fact trades is taxed as a trader. Changing a code changes nothing on the tax side, and it will not, by itself, create or remove a VAT registration obligation either.

Timing: when to make the change

For a property company the timing question almost always comes down to whether a lender is about to look at the register. If a mortgage application is in prospect, correct the codes first and let the change settle on the public record before the application goes in, because a decision-in-principle can be declined on the classification alone and re-applying after a decline is slower than filing beforehand. An updating confirmation statement filed online is normally processed quickly, so this is usually a matter of days rather than weeks.

Where nothing is pending, waiting for the annual renewal is perfectly sensible and marginally simpler, because the codes are corrected as part of a filing that was going to happen anyway. The only caution is not to leave a wrong code in place indefinitely on the assumption that nothing reads it. Lenders, insurers, credit reference agencies and prospective buyers all pull the same record.

One practical note on early filing: because a confirmation statement resets the next due date to twelve months from the date filed, an updating statement moves your renewal date forward. That is harmless, but it is worth knowing if your compliance calendar or your accountant's diary is built around the original date.

What happens after you file

Once Companies House accepts the confirmation statement, the updated codes appear against the company on the public register and on the Find and Update Company Information service. Nothing further is required. There is no confirmation letter to chase, no separate notification to make, and no obligation to tell HMRC about the classification itself.

The one step worth taking is to look at the company's own page on the register afterwards and read the codes back. Acceptance is not something to assume, and the check takes a moment. Where a filing has been rejected, Companies House contacts the presenter, so make sure the email address on the record is one you monitor. If the underlying activity of the company has genuinely changed rather than merely been misdescribed, that change may carry consequences of its own for VAT, for the basis on which profits are taxed, or for the terms of an existing mortgage, and those are worth reviewing separately from the filing.

For the wider picture of how a property company is structured, financed and taxed, start from our SPV company hub.