SimpleReturns

Company tax returns for property investment companies

Reviewed by Lee Jones, Founder · Updated 16 July 2026
The short answer

The filing duty is the same for every limited company in the UK: once a year, your company must send HMRC a Company Tax Return (a form called the CT600) with a set of accounts, even in a year it made a loss. Your version of it as a property company looks like this: the rent your tenants pay is your company's income, the real costs of running the lettings come off, and your company pays Corporation Tax on the profit that is left. And here is the part that catches people out in a good way: because a company owns the property, it is treated more kindly than a personal landlord on mortgage interest.

Official source. This guide is a plain-English summary of official GOV.UK guidance, not advice. The authoritative source is Company Tax Returns on gov.uk. Always rely on that over our summary.

What counts as your company's income?

One thing to hold onto from the start, because it changes everything below: your property is owned by a company, not by you personally. So none of the rules you may have read about personal landlords, the ones who own a buy-to-let in their own name, apply here. The company is its own taxpayer, and it pays Corporation Tax on its rental profit. That single fact is why so many landlords hold property through a company in the first place.

The rent. Every payment your tenants make for the use of your company's property is company income, whether it is a monthly rent on a flat, a commercial lease, or a short holiday let. It lands in the company's bank account and belongs to the company, not to you.

One small but important point about where it goes on the form. Rent is not the same as the turnover of a trading business, so it does not sit in the trading-turnover box on the CT600. It goes in a separate place for property income (box 190). Our guide on property income on the CT600 (box 190) shows you exactly where.

And Corporation Tax is not worked out on the rent you collected. It is worked out on the profit: rent in, minus the genuine costs of running the lettings. Say your company collected £24,000 in rent across the year and spent £5,000 keeping the properties let. The tax is worked out on the £19,000 that is left, not the £24,000.

Two rules trip people up. The return is due even in a quiet year: if HMRC has asked your company for a return, it must go in even at a loss, with nothing to pay. And filing late now costs £200 from the very first day.

What can your company claim?

The test is simple: was the money spent to earn the rent? If yes, it usually comes off the profit before tax. Here are the costs a property company genuinely has:

  • Mortgage or loan interest. This is the big one, and it is the reason a company often works out cheaper than owning in your own name. A personal landlord can no longer take all their mortgage interest off their rent; their relief is limited to the basic rate of personal tax. A company is not caught by that. Your company can count its allowable loan interest as a cost of earning the rent.
  • Repairs and upkeep. Fixing a broken boiler, mending a roof, repainting, replacing a worn carpet with a similar one: the everyday work of keeping a property in a lettable state. (There is a catch on this one, coming up next.)
  • Letting agent fees. What you pay an agent to find tenants and manage the let.
  • Landlord insurance. Cover you buy purely because the company lets property.
  • Ground rent and service charges. Where the property is leasehold and the company has to pay them to keep the lettings running.

Keep a record of each cost. A company cost has to be for the business to come off the tax. If something is really part personal, keep the personal side out of the company, because putting a personal cost or an asset you also use privately through the company can create an extra personal tax charge (a "benefit in kind") rather than a part-claim. If you are not sure, that is one to check with an accountant.

The trap: a repair is not the same as an improvement

This is the one that catches property companies most, so it is worth slowing down on. A repair puts something back to the condition it was in: mending, replacing like with like, keeping the property doing its job. That is an allowable running cost and comes off your rental profit.

An improvement is different. If you upgrade the property beyond what it was, say you replace a basic kitchen with a top-of-the-range one, or build an extension, that is not a running cost. It is treated as money spent on the property itself (capital), and it does not come off your rental profit in the same way. In HMRC's own words it is "a question of fact and degree" in each case, so the line is not always obvious. If a big job sits somewhere between a repair and an improvement, that is a fair point to get checked rather than guess.

There is a second thing worth knowing for the day you sell. When a company sells a property, that is a separate event from the yearly rent, and the company usually pays Corporation Tax on the gain (the profit on the sale). Working out a property sale properly, with the costs and reliefs that go with it, is genuinely a job for an accountant, and there is no shame in that.

What does filing look like with us?

You upload your company's bank statement and answer a few plain-English questions. We sort the year's money into the right places, put the rent where it belongs, take off the allowable costs of running the lettings, work out the profit and the Corporation Tax, and build both filings: the tax return for HMRC and the accounts for Companies House. You see every figure before anything is sent. It is free to start, and one payment of £99 covers both filings.

Common questions

Is the rent my company collects all taxed?

No. Corporation Tax is worked out on profit, not on the rent collected. The rent is your company's income, then the genuine costs of running the lettings come off, and the tax is worked out on the profit that is left.

Where does the rent go on the CT600?

Rent is not the same as the turnover of a trading business, so it does not sit in the trading-turnover box. It goes in a separate place for property income, box 190.

Can my company claim its mortgage interest?

Yes. A personal landlord's relief for mortgage interest is limited to the basic rate of personal tax, but a company is not caught by that. Your company can count its allowable loan interest as a cost of earning the rent.

What is the difference between a repair and an improvement?

A repair puts the property back to the condition it was in, replacing like with like, and comes off your rental profit. An improvement upgrades the property beyond what it was, which is treated as capital and does not come off the rental profit in the same way.

Want your property company's return filed for you?

You upload your company's bank statement and answer a few plain-English questions. We build your accounts and the CT600, put the rent where it belongs, take off the allowable costs, work out the profit and the Corporation Tax, and show you every figure before anything is sent. Free to start, and one payment of £99 covers both filings, the tax return to HMRC and the accounts to Companies House.

Start your return

And if you hold property through several linked companies, have a large portfolio, or are selling a property this year, an accountant may be the better fit for that part, and that is an honest call to make.

General guidance, not advice. This guide explains how the rules generally work for small UK limited companies. It isn't tax advice for your specific situation, if you're unsure, check with us or an accountant.