UK Property Income Tax 2026/27: Why Rental Landlords Are Finally Restructuring as Limited Companies — and the Section 24 Maths That Forces the Issue

Your buy-to-let portfolio of three flats in Manchester generated £42,000 of rental income in the 2024/25 tax year, and your accountant's letter for 2025/26 shows your taxable profit calculated at £38,000 — yet your actual cash retained after mortgage interest, ground rent, repairs, and management was £18,500. You're being taxed on income you never received. This is the structural reality of Section 24 of the Finance Act 2015, fully phased in since April 2020 and now compounding into the 2026/27 tax year. For higher-rate-tax landlords with mortgages, the personal-name structure has stopped working — and the question of whether to incorporate is no longer about saving a few percentage points, but about whether the rental business is viable at all.

The 2024 Finance Act introduced no further restrictions on individual landlords, but it also reinforced the existing framework: mortgage interest on residentially-let property held in personal names cannot be deducted from rental income. Instead, you receive a 20% basic-rate tax credit on the interest. For a basic-rate-taxpayer landlord this approximates the old position — but for higher-rate (40%) and additional-rate (45%) taxpayers, the effective tax on rental profit can exceed 70%, even occasionally exceeding 100% when interest rates are high relative to rental yields. This is what's pushing the surge of incorporations in 2025 and 2026.

The Section 24 maths in practice

Take a higher-rate-taxpayer landlord with three properties: total rental income £42,000, mortgage interest £18,000, other allowable expenses £6,000. The pre-2017 calculation: rental profit £18,000, tax at 40% = £7,200. Net cash to landlord: £10,800.

The 2026/27 calculation under Section 24: rental profit treated as £42,000 minus £6,000 (other expenses only) = £36,000. Tax at 40% = £14,400. Less 20% basic-rate credit on £18,000 mortgage interest = £3,600. Net tax: £14,400 - £3,600 = £10,800. Net cash after tax and mortgage interest: £42,000 - £18,000 - £6,000 - £10,800 = £7,200.

Same income, same costs, same property. Tax bill went from £7,200 to £10,800 — a £3,600 annual increase. After-tax cashflow dropped from £10,800 to £7,200. That's a 33% cut in the landlord's take-home from the same portfolio. And we've assumed nothing went wrong — no voids, no boiler replacement, no rent increase. This is the reason serious landlords are restructuring in 2026.

The limited company alternative

A limited company landlord pays Corporation Tax (currently 25% for profits above £250,000, 19% for profits below £50,000, marginal relief in between) on rental profit calculated normally — that is, with full deduction of mortgage interest. For our example landlord: rental profit £42,000 - £18,000 - £6,000 = £18,000. Corporation Tax at 19% (small profits rate) = £3,420. Cash retained in company: £14,580.

That £14,580 isn't immediately your money, though. To extract it personally, you draw a salary or dividend. A £14,580 dividend, after the £500 dividend allowance, is taxed at 33.75% for higher-rate taxpayer = £4,752 personal tax. Net to landlord personally: £14,580 - £4,752 = £9,828.

So personal-name landlord nets £7,200; limited-company landlord nets £9,828. The limited company is £2,628 better off in 2026/27 — but only if you extract the cash. If you reinvest the profit into another property purchase, the limited company is dramatically better because it retains the full £14,580 to compound, vs the personal landlord's £7,200 after personal tax.

The costs of incorporating that erode the gain

The £2,628 annual gap above is meaningful but not transformative. The decision to incorporate has to weigh up substantial one-time and ongoing costs that erode the saving.

Stamp Duty Land Tax on transfer. Moving an existing rental property from personal ownership to a limited company is a sale and triggers SDLT at the higher rate (3% surcharge for company-owned residential property, applied across all bands). For a £200,000 property, SDLT on transfer is £7,500. For a £350,000 property, £20,000. For a £500,000 property, £37,500. This is the single biggest barrier to incorporation, and it's not avoidable for most existing landlords.

Capital Gains Tax on the disposal. Transferring property to a company at market value is a CGT event. The landlord pays CGT (24% for residential property in 2026/27 after the rate harmonisation) on any gain since purchase. For a property bought for £150,000 now worth £250,000, that's £24,000 CGT — payable at the moment of incorporation, not from rental cashflow.

Mortgage refinancing costs. Most personal-name BTL mortgages can't transfer to a company structure. You need to refinance to a limited-company BTL mortgage (commonly priced 0.4-0.7% above personal-name BTL). Arrangement fees of 1-2% on each loan, plus valuation fees, plus legal fees — typically £3,000-£6,000 per property. For a three-property portfolio, that's £9,000-£18,000 in transaction costs.

Adding up: SDLT £20,000-£37,500, CGT £24,000+, refinancing £15,000. Total cost to incorporate a typical mid-size portfolio: £50,000-£75,000 of upfront cash. At an annual saving of £2,628, the breakeven is 19-29 years.

The "incorporation by acquisition" route

This is why most landlords incorporating in 2025-2026 don't move existing properties — they buy new ones inside a limited company while keeping older properties in personal names. The new-purchase route avoids the SDLT and CGT of transfer entirely. The limited company starts from scratch, builds a portfolio inside the corporate structure, and benefits from the full mortgage interest deduction on every new acquisition.

This works particularly well for landlords actively expanding portfolios. The personal-name properties continue to operate under Section 24 (sub-optimally but tolerably), while all new acquisitions go into the company where the tax structure works properly. After 5-10 years of new purchases, the limited company portfolio dominates the holdings, and the personal-name properties are eventually sold off as opportunity arises.

Section 162 incorporation relief: the narrow exception

One CGT relief sometimes applies on incorporation: Section 162 incorporation relief allows the gain to be rolled into the share value of the new company rather than crystallised at transfer. The condition is that the landlord operates a property "business" — defined by HMRC as substantially more than passive ownership. Recent case law (Ramsay v HMRC, 2013, and subsequent rulings) requires the landlord to be actively involved at a commercial scale. A four-property portfolio managed by a letting agent typically does not qualify. A 25-property portfolio with personal management activity probably does. Get specialist advice — Section 162 has been the subject of multiple HMRC challenges, and amateur use of it has cost landlords substantial back-tax bills.

The Stamp Duty saving for partnerships

Property partnerships (formal partnerships, not joint ownership) can sometimes incorporate without SDLT under Schedule 7 of the Finance Act 2003. The conditions are technical: the partnership must have been operating as a genuine commercial partnership for sufficient time, and the partners must own the limited company shares in the same proportion as their partnership interests. Many landlords with their spouse have informal joint ownership rather than a registered partnership — that doesn't qualify. To use the SDLT exemption, you'd need to formalise as a partnership and operate as such for a meaningful period before incorporation. This is achievable but takes years of planning.

The 2026/27 specific changes to know

The Autumn 2025 Budget did not introduce major new restrictions on landlords, but several technical changes apply to 2026/27 returns. The annual investment allowance for furnished holiday lets dropped to zero — what used to be a meaningful relief on equipment purchases for FHL portfolios no longer applies. Mortgage interest 20% credit remains capped at the lower of (a) interest itself, (b) rental profits, or (c) the amount that takes total income below the higher-rate threshold — meaning some landlords with low rental profits and high other income don't get the full credit.

MTD ITSA (Making Tax Digital for Income Tax) is now mandatory for all landlords with rental and self-employment income above £30,000 from April 2026. Quarterly digital submissions to HMRC, plus the year-end final return — through compatible software (FreeAgent, QuickBooks, Xero, plus several specialist landlord platforms). The compliance cost is real: typically £25-£50 per month for software, plus the time of quarterly filings. Below £30,000 turnover, MTD is voluntary but expected to extend down to £20,000 from April 2027.

The decision framework that actually works

If you're a higher-rate taxpayer landlord with a portfolio and the question is whether to incorporate, the answer depends on three variables: (1) your existing tax bill under Section 24, (2) whether you're expanding the portfolio or holding steady, (3) the SDLT and CGT costs of transferring existing properties.

If you have 1-3 properties bought before significant capital growth, with the intention of holding rather than expanding, incorporation typically does not pay off. The SDLT and CGT swallow many years of tax saving. Stay personal, accept Section 24, and focus on debt reduction or sale of marginal properties.

If you have 4+ properties or are actively expanding, incorporation through new acquisitions starts to make clear sense, with the existing portfolio either left in place or sold opportunistically. Use a SPV (special purpose vehicle) limited company per property or per portfolio segment, depending on lender requirements.

If you're starting now with first-property buy-to-let intent, buy through a limited company from day one. The lender pricing premium is real but the structural tax efficiency is decisive. The 2026/27 environment will not become more landlord-friendly under either main political party — Section 24 is here to stay, and further restrictions are politically more likely than reversals.