CT600 for Property Companies: Landlord Corporation Tax Guide 2026

More UK landlords than ever are holding buy-to-let properties through limited companies. Since the Section 24 mortgage interest relief restrictions hit personal landlords in 2020, incorporation has become the default tax planning strategy — and that means filing a CT600 with property-specific rules.

If you're a director of a property company, this guide covers everything you need to know about corporation tax on rental income, mortgage interest deductions, capital allowances, property disposals, and how to file your CT600 correctly in 2026.

Why Property Companies File CT600 Differently

A property investment company isn't like a typical trading business. The differences that affect your CT600:

• Income is classified as property income (non-trading), not trading income — this affects which CT600 boxes you use
• Mortgage interest is fully deductible at the company level (unlike personal landlords post-Section 24)
• Capital allowances on furnishings and fixtures follow specific property rules
• Property disposals trigger chargeable gains reported on the CT600
• Rental losses have different offset rules compared to trading losses

Understanding these distinctions is essential for accurate filing. If you're coming from a personal landlord background, forget what you knew about self-assessment property income — company tax rules are fundamentally different.

Reporting Rental Income on Your CT600

Where Rental Income Goes

On the CT600, property income is reported in the property income section, not as trading profits. Specifically:

• Box 190 — Income from UK property (gross rental income)
• Box 195 — Net property income (after deducting allowable expenses)

This is different from Box 155 (trading profits), which is where service companies and trading businesses report their income.

Important: If your property company also provides property management services or develops properties for sale, you may have both trading and property income — these must be separated on your CT600.

Calculating Gross Rental Income

Your gross rental income includes:

• Monthly/weekly rent received or receivable
• Any service charges you receive from tenants
• Insurance recovery payments
• Any premiums received for granting a lease (complex rules apply)
• Forfeited deposits where the tenant breached the agreement

Report income on an accruals basis — the rent due in the accounting period, not just cash received. If a tenant owes December rent but pays in January, December's rent belongs in the current period's CT600.

What About Void Periods?

Void periods (when the property is empty between tenancies) don't generate income, but the expenses during void periods are still deductible — as long as you intend to re-let the property. This includes mortgage interest, insurance, and council tax during void periods.

Mortgage Interest Deductions: The Property Company Advantage

This is the biggest reason landlords incorporate. Here's how it works for your CT600:

Full Deduction at Company Level

Unlike personal landlords who are now restricted to a 20% basic-rate tax credit on mortgage interest, a property company can deduct 100% of mortgage interest as an expense against rental income.

On your CT600, mortgage interest is a straightforward expense that reduces your property income figure in Box 195.

Example:

Compare this with a higher-rate personal landlord who'd pay tax on the full £36,000 less other expenses (£30,000), with only a 20% credit on the interest — resulting in significantly higher tax.

What Qualifies as Deductible Interest?

• Buy-to-let mortgage interest — the primary deduction
• Arrangement fees — spread over the life of the mortgage, or deducted in full in some cases
• Remortgage costs — deductible if the remortgage is for the buy-to-let business
• Bridging loan interest — deductible if used to acquire a rental property
• Interest on directors' loans to the company used for property purchase — deductible (but check the directors' loan account implications)

Watch Out: Section 455 Tax on Intercompany Loans

If the company borrows from you (the director) to fund property purchases, the interest paid to you is deductible for the company. However:

• You'll pay personal income tax on the interest received
• If the directors' loan account is in the wrong direction (you owe the company), Section 455 tax applies at 33.75%

Keep your loan account meticulously documented.

Allowable Expenses for Property Companies

Beyond mortgage interest, property companies can deduct a wide range of expenses on the CT600:

Repairs and Maintenance

• Routine repairs (plumbing, electrical, decorating between tenancies) — fully deductible
• Like-for-like replacements (new boiler replacing old boiler) — fully deductible
• Improvements (adding an extension, upgrading single glazing to double glazing) — not deductible as revenue expense, but added to the property's base cost for capital gains purposes

Key distinction: A repair restores an asset to its original condition. An improvement goes beyond that. Replacing a broken kitchen with a similar one is a repair. Replacing a basic kitchen with a premium kitchen is partly an improvement.

Insurance

• Buildings insurance — deductible
• Landlord liability insurance — deductible
• Rent guarantee insurance — deductible
• Legal expenses insurance — deductible

Letting Agent and Management Fees

• Letting agent fees for finding tenants — deductible
• Ongoing property management fees — deductible
• If you manage properties yourself, consider paying yourself a salary through the company for this work

Professional Fees

• Accountancy fees for preparing accounts and CT600 — deductible
• Legal fees for new tenancy agreements — deductible
• Legal fees for purchasing property — not deductible (added to base cost instead)
• Legal fees for evicting a tenant — deductible

Ground Rent and Service Charges

If your property is leasehold:

• Ground rent — deductible
• Service charges — deductible (unless they relate to improvements)
• Lease extension costs — capital expenditure (added to base cost)

Other Deductible Costs

• Council tax during void periods
• Utility bills you pay as landlord
• Advertising for tenants
• Home office costs if you manage the property business from home
• Safety certificates (gas, electrical, EPC)
• Travel to properties for inspections and management

For the complete list, see our allowable expenses guide.

Capital Allowances for Property Companies

Capital allowances let you deduct the cost of certain assets over time, reducing your CT600 tax bill. For property companies, the rules are specific:

Furnished Residential Lettings

Since April 2016, the old "wear and tear allowance" (10% of rent for furnished properties) was replaced by the Replacement of Domestic Items Relief:

• You can claim the cost of replacing furnishings, appliances, and kitchenware
• This covers sofas, beds, carpets, curtains, white goods, televisions, etc.
• The claim is for like-for-like replacement only — if you replace a basic washing machine with a premium one, you claim only the cost of a basic equivalent
• First-time furnishing of a property is not covered — those costs are capital

Integral Features and Plant & Machinery

For certain property features, capital allowances apply:

Integral features (capital allowances at special rate pool — 6% writing down allowance):

• Electrical systems
• Cold/hot water systems
• Heating, ventilation, air conditioning
• Lifts and escalators

Plant and machinery in common areas (main rate pool — 18% writing down allowance, or AIA/full expensing):

• Security systems, CCTV
• Fire alarm systems
• Communal furniture (in HMOs or serviced accommodation)

Important Limitation: Residential vs Commercial

The availability of capital allowances differs:

For commercial property (offices, retail, industrial), the Structures and Buildings Allowance (SBA) provides a 3% annual deduction on the construction or acquisition cost — a significant benefit.

Corporation Tax on Property Disposal (Capital Gains)

When your property company sells a property, the chargeable gain is subject to corporation tax — not capital gains tax. This is a crucial distinction.

How to Calculate the Gain

The gain calculation follows corporate rules:

1. Sale proceeds — the actual sale price
2. Less acquisition cost — what the company paid for the property
3. Less incidental costs of acquisition — legal fees, stamp duty (SDLT) on purchase
4. Less enhancement expenditure — the cost of improvements (not repairs)
5. Less incidental costs of disposal — estate agent fees, legal fees on sale
6. Equals chargeable gain

Unlike personal CGT, there is no annual exempt amount and no entrepreneurs' relief for company property disposals.

Indexation Allowance (Frozen)

Companies used to benefit from indexation allowance — increasing the base cost by inflation. This was frozen at December 2017. If your company bought the property before January 2018, you can still claim indexation up to December 2017, which reduces the gain.

Corporation Tax Rate on Gains

The gain is added to your other profits and taxed at the standard corporation tax rates:

• 19% if total profits (including the gain) are under £50,000
• 25% if over £250,000
• Marginal relief between £50,000 and £250,000

Reporting on Your CT600

Property disposals go on the CT600 supplementary page CT600C (Capital gains). You'll need to provide:

• Details of the property disposed of
• Dates of acquisition and disposal
• Computation of the gain
• Any reliefs claimed

See our supplementary pages guide for more detail.

Extracting the Sale Proceeds

After the company pays corporation tax on the gain, extracting the remaining cash to you personally will trigger personal tax:

• Dividends — taxed at dividend rates (8.75% basic, 33.75% higher, 39.35% additional)
• Company liquidation — potentially subject to Business Asset Disposal Relief (BADR) if the company qualifies, giving a 10% effective rate up to £1 million lifetime limit
• Close company capital distribution — the "moneyboxing" anti-avoidance rules may apply

Plan the extraction strategy before selling the property. The combined company + personal tax rate needs careful calculation.

Stamp Duty Land Tax (SDLT) and Your CT600

When your company purchases a property, it pays SDLT at the higher rates (an additional 5% surcharge for companies purchasing residential property, on top of the 3% additional property surcharge — total 8% above standard rates for residential).

On your CT600:

• SDLT is not deductible as a revenue expense
• SDLT is added to the base cost of the property for capital gains purposes
• This means SDLT reduces the chargeable gain when you eventually sell

For properties over £500,000, the Annual Tax on Enveloped Dwellings (ATED) may also apply — requiring a separate annual return and potentially significant charges. This is separate from your CT600 but worth noting.

Property Losses: How to Handle Them on Your CT600

If your property company makes a loss (expenses exceed rental income), the treatment depends on the type of loss:

Property Income Losses

• Can be carried forward and set against future property income of the same company
• Cannot be offset against other types of income (e.g., trading income) in the same period
• This is different from trading losses, which have more flexible offset options

Trading Losses (Property Development Companies)

If your company develops property for sale (this is trading, not investment), trading losses can be:

• Set against other profits of the same period
• Carried back one year
• Carried forward against future trading profits

For loss rules in detail, see our corporation tax losses guide.

Multiple Properties and Portfolio Management

Most property company directors own multiple properties. CT600 considerations:

Single Company vs Multiple Companies

Some landlords put each property in a separate company. Consider:

• Multiple companies = multiple CT600 filings, multiple sets of accounts
• Each company gets its own £50,000 small profits threshold — but associated company rules divide the thresholds
• 4 associated companies = £12,500 small profits limit each
• Administration costs multiply

For most landlords with a small portfolio (under 10 properties), a single company is simpler and usually more tax-efficient.

Record Keeping Per Property

Even with all properties in one company, keep separate records per property:

• Income and expenses per property
• Capital expenditure per property
• Void period dates per property
• This makes your CT600 preparation much easier and supports any HMRC enquiry

See our record keeping guide for what you need to retain and for how long.

Filing Your Property Company CT600: Step by Step

Step 1: Reconcile Rental Income

• Match rent received per bank statements to tenancy agreements
• Accrue any rent due but not yet received
• Reconcile with letting agent statements if applicable

Step 2: Categorise Expenses

Separate your expenses into:

• Revenue expenses (deductible in full this year)
• Capital expenditure (eligible for capital allowances or added to property base cost)
• Disallowable items (if any)

Use our disallowable expenses checklist to avoid common errors.

Step 3: Calculate Capital Allowances

If you've bought qualifying plant and machinery, calculate your capital allowances claim:

• AIA (up to £1 million per year for qualifying expenditure)
• Writing down allowances (18% main rate, 6% special rate)
• Replacement of domestic items relief

Step 4: Prepare Accounts

Your accounts need to show:

• Profit and loss account with property income and expenses clearly presented
• Balance sheet showing property at cost, mortgage liabilities, and retained earnings
• Accounts must be filed in iXBRL format

Step 5: Complete the CT600

For property companies, pay special attention to:

• Box 190/195 — property income (not Box 155)
• Capital allowances boxes — if claiming
• CT600C — if you disposed of a property
• CT600A — if you have loans to participators (directors' loan accounts)

Our CT600 box-by-box guide walks through every section.

Step 6: File and Pay

• CT600 filing deadline: 12 months after accounting period end
• Payment deadline: 9 months and 1 day after accounting period end
• Late filing penalties: start at £100 — don't risk it

FAQ: CT600 for Property Companies

Can I claim mortgage interest in full on my CT600?

Yes. Unlike personal landlords who are restricted to a 20% basic-rate tax credit, companies can deduct 100% of mortgage interest as an expense against rental income on the CT600. This is one of the main advantages of holding property in a company.

Do I need to file a CT600 if my rental income doesn't cover the mortgage?

Yes. You must file a CT600 even if the company makes a loss. The loss can be carried forward to offset against future property income, so filing accurately is important even in loss-making years. See our nil return guide if the company had no activity at all.

How is capital gains tax different for property companies?

Property companies don't pay capital gains tax — they pay corporation tax on the chargeable gain. The gain is added to other profits and taxed at 19%-25%. There's no annual exempt amount and no entrepreneurs' relief. However, indexation allowance (frozen at December 2017) may reduce the gain for properties held since before 2018.

Can I transfer personally-owned properties to my company?

Yes, but this triggers SDLT on the transfer (at market value) and CGT on you personally. It's a complex area where professional advice is essential. The CT600 for the first year will include the property at the transfer value.

What about the Section 24 mortgage interest restriction?

Section 24 only applies to individual landlords. If your property is held in a limited company, Section 24 does not apply. Your company claims full mortgage interest relief against rental income. This is the primary tax motivation for landlord incorporation.

How much does property company CT600 filing cost?

Specialist property accountants typically charge £500-£1,500+ per year for property company accounts and CT600 filing. With Taxpipe, you can file for £59 — including iXBRL accounts and HMRC submission.

Do I need supplementary pages for my property CT600?

You'll likely need: the property income section of the core CT600, plus CT600C if you've sold a property, and CT600A if you have a directors' loan account. Our supplementary pages guide explains which ones you need.

What accounting standard should my property company use?

Most small property companies can use FRS 105 (micro-entity regime) if they qualify, which simplifies the accounts significantly. Larger companies may need FRS 102. The choice affects presentation but not the CT600 tax computation.

File Your Property Company CT600 with Taxpipe

Managing a property portfolio is enough work without overpaying for CT600 filing. Many property company directors pay £1,000+ per year to accountants for straightforward property company accounts and tax returns.

Taxpipe offers a smarter approach:

• £59 flat fee — regardless of the number of properties in the company. Check our pricing →
• Property income reporting — our guided flow handles property-specific CT600 boxes
• iXBRL accounts included — no separate charge for accounts preparation
• HMRC-recognised — your CT600 files directly to HMRC
• Built for directors — plain English guidance, not accounting jargon

Your tenants pay rent, your mortgage payments go out, your expenses are tracked. You've done the property management. Let Taxpipe handle the tax filing.

Start filing your property company CT600 →

Estimate your tax bill first with our corporation tax calculator.

This guide provides general information about corporation tax for property companies and does not constitute tax advice. Property disposals, incorporation of existing portfolios, and ATED situations may require specialist advice. For straightforward property company CT600 filing, Taxpipe makes it simple at £59.

Related Reading

• Buy-to-Let Through a Company: Tax Guide
• Corporation Tax for Property Companies: A Complete Landlord Guide
• Annual Investment Allowance (AIA): Claim Up to £1 Million in Tax Relief