Financing a Property Development: How the Finance Is Taxed

The rate on a development facility is only half of what it costs you. The other half is how the interest, the fees and the profit are taxed, and that turns almost entirely on one question that UK property tax has settled long before you drew the loan: are you trading or investing? Get that answer right and the finance is relieved cleanly against your profit. Get it wrong and you can find yourself paying income tax on a gain you assumed was a capital one, or losing 80% of your interest relief to a restriction you did not think applied.

This guide is about the tax treatment of the finance behind a scheme, not about arranging it. For how a development facility actually works (loan to gross development value, loan to cost, staged drawdowns and the day-one land advance) see our development finance guide. Here we deal with what HMRC does with the interest.

Why trading versus investment decides everything

A property developer holds the scheme as trading stock. The costs of building it, including the finance, are costs of the trade, and the profit on sale is trading income. A property investor holds the finished building as a capital asset. The costs of holding it are finance costs of a property business, and the eventual disposal is a capital gain. Those are two completely different tax regimes, and the same person doing the same physical works can fall into either depending on their intention and conduct.

Property Tax Partners already owns the detailed decision on which side of the line you sit. Rather than repeat it, we point you to it: start with trading versus investment income for property and the self-test in are you a property investor or a developer. If you are building or converting residential units to sell, also read the residential property developer tax guide. What follows assumes you have that classification straight, because every figure below flips depending on it.

Development finance interest for a property trader

If you are trading, interest on the money you borrowed to fund the development is a cost of the trade. It is deductible under the ordinary wholly-and-exclusively test, and HMRC's guidance on property developers and the treatment of interest sits in the Business Income Manual (see BIM51105 onwards for developers and BIM45650 onwards for the incidental costs of loan finance). Relief is not in doubt for a genuine trade. The live question is timing, and that is an accounting question before it is a tax one.

Under FRS 102 a developer can adopt one of two policies for borrowing costs that are directly attributable to bringing the scheme to its saleable state:

• Capitalise into work in progress. The interest is rolled into the cost of the trading stock and sits on the balance sheet as WIP. It is relieved when the units are sold, matched against the sale proceeds in the profit and loss account. Relief is deferred to the period of sale.
• Expense as incurred. The interest is charged to profit and loss as it accrues, giving relief in the period it arises, even before any unit is sold.

The tax generally follows the accounts, so the policy you choose changes when you get the relief, not whether. On a scheme that straddles two or three year ends, capitalising can push a large slice of relief into a later, higher-profit year (useful) or strand it if the scheme is loss-making (unhelpful). The policy has to be applied consistently, so this is a conversation to have with your accountant before the first set of accounts, not a switch to flick afterwards. For a company, the interest runs through the loan relationship rules in Part 5 of CTA 2009 and is deductible in computing the trading result, subject to the corporate interest restriction on larger borrowing.

Worked example: a £350k commercial-to-residential conversion

Take a converter who buys a tired commercial building for around £350,000 and turns it into flats to sell. Over the life of the scheme the development facility accrues roughly £40,000 of interest (however the facility itself is priced; development finance pricing moves with the market, so treat any rate as indicative and confirm current terms with a lender or broker, as at July 2026). The building is a trade: bought to convert and sell, financed for resale, sold on completion. Here is how that £40,000 behaves.

• As a trader, capitalising into WIP. The £40,000 is added to the cost of the flats and sits in work in progress. When the units sell, it is relieved against the sale proceeds as part of cost of sales. The trading profit on the scheme, taxed as income (income tax rates for an individual, or corporation tax at 19% or 25% for a company), is £40,000 lower than it would be without the finance. Full relief, given on sale.
• As a trader, expensing. The same £40,000 is charged to profit and loss as it accrues. If the build runs across two accounting periods, part of the relief lands in the earlier year. Same total relief, earlier timing.
• If HMRC treats the same person as an investor. Now the picture changes entirely. If the flats are held to let rather than sold, and held personally, the interest is a finance cost of a residential property business, and Section 24 restricts relief to a 20% basic-rate tax reducer. A higher-rate individual gets relief worth £8,000 on that £40,000 rather than deducting the whole amount. And the profit, when the property is eventually sold, is a capital gain rather than trading income only if the asset was genuinely held as an investment throughout.

The physical work is identical in all three. The tax is not. That gap is why the classification question is worth settling before you draw the facility.

Interest for an investor holding the finished asset

If you are genuinely an investor (you built or bought to hold and let, not to sell), the finance is not a trading cost. It is a finance cost of your property business, and the rules are the ones property already documents in depth. For an individual holding a completed residential dwelling, section 272A ITTOIA 2005 (Section 24) restricts relief on dwelling-related loans to a 20% basic-rate tax reducer, not a full deduction. For a company, or for commercial property, that restriction does not apply and the interest is relieved in full. This is the same body of rules that governs a buy-to-let mortgage, so the interest on a bridge or a development loan that ends up funding a held-to-let residential asset is treated the same way. Our companion page on whether bridging loan interest is tax deductible sets out the individual-versus-company and residential-versus-commercial splits in full.

Rolled interest, arrangement fees and the incidental costs of finance

Development facilities rarely have you paying interest monthly out of pocket. Interest is usually rolled or retained into the facility, accruing and drawn down against the loan rather than serviced. For a trader on an accruals basis this generally does not change the relief: the interest is deductible as it accrues, whether or not cash has changed hands, so rolled interest is relieved as it builds up, not only when the loan finally redeems.

The fees around the facility (the arrangement fee, broker fee, the lender's valuation and legal costs, commitment fees and any exit fee) are the incidental costs of obtaining loan finance. For a trade these are generally deductible alongside the interest, and HMRC deals with them as incidental costs of finance in its manuals (see BIM46435 on the incidental costs of obtaining finance). If your policy is to capitalise the interest into work in progress, the associated finance fees will usually follow it there. Be careful to separate the costs of the finance from the costs of acquiring the land or asset: the latter are capital costs of the stock, not finance costs, and are dealt with as part of the cost of the development.

Mezzanine and JV finance: interest versus profit share

Most schemes above a certain size are not funded by a single senior facility. They are a stack: senior debt, then a top-up layer, then the developer's own equity. That top-up layer is either mezzanine debt or joint venture equity, and the two are taxed on opposite principles.

• Mezzanine is debt. The higher coupon is interest, relieved like any other finance cost, subject to the corporate interest restriction and, where the lender is connected, transfer-pricing rules. A profit share bolted onto a mezzanine coupon needs to be tested: is it really interest, or is it a distribution of profit dressed as a return on debt?
• JV equity is not debt. A JV partner puts in cash for a share of the profit, not for interest. There is no interest deduction. The tax then depends on the JV structure, a partnership, a special purpose company or a purely contractual arrangement, and a profit share paid out of a company can be a non-deductible distribution rather than a deductible cost.

The choice between borrowing the gap and giving away a share of the profit is a cost-versus-dilution decision with a real tax dimension attached. We cover the finance mechanics and the capital stack in the mezzanine and JV finance guide; the point here is simply that an interest cost and a profit share are not interchangeable for tax, and the structure should be priced with that in mind before anyone signs.

The condition D convert-and-flip trap

The most common way a developer trips up is assuming a flip is taxed as a capital gain. It usually is not. Buying a property, adding value and selling on has the classic badges of a trade, and on top of the case law HMRC has a statutory hook: the transactions-in-UK-land rules can reclassify a gain as trading income where a main purpose of acquiring or developing the land was to realise a profit on its disposal. The specific version that catches landlord-developers is the condition D main-purpose test, and we set the trap out in full in condition D, the convert-and-flip trap for landlord-developers.

The practical consequence is direct. If you are caught, your profit is income, not a capital gain, so it is taxed at income tax or corporation tax rates rather than at the 18% or 24% residential CGT rates, and the £3,000 annual exempt amount is irrelevant. The interest, correspondingly, is a trading finance cost. Assuming CGT treatment on a scheme that is really a trade is one of the most expensive errors in this area.

SDLT, VAT and the income-versus-CGT exit in brief

Three more points sit around the finance and are worth flagging, though each has its own depth elsewhere:

• SDLT on acquisition. You pay stamp duty land tax (or LBTT in Scotland, LTT in Wales) when you buy the site, at the rate appropriate to the property type. It is a cost of the development, not of the finance, but it affects the cash you need alongside the deposit.
• VAT on the works. Constructing new dwellings, or converting a non-residential building such as an office into flats, is zero-rated, so the developer can register and recover input VAT on construction costs. Refurbishing an existing dwelling is generally standard-rated with no recovery, and selling an existing residential property is exempt. Commercial elements can bring in the option to tax. The VAT position moves the cash flow materially and is worth modelling early.
• Income versus CGT on the exit. As above, a trader's profit on sale is income; only a genuine investor's disposal is a capital gain. The interest treatment and the exit treatment travel together: they are both downstream of the trading-versus-investment call.

Scope, regulated finance and where the tax review fits

This is educational content on the tax treatment of development finance. It is not a financial promotion and does not arrange, introduce or recommend any lending. Development finance for a genuine business or investment purpose sits outside the consumer-credit and regulated-mortgage perimeters, but promoting the credit itself is a restricted activity under section 21 of the Financial Services and Markets Act 2000, so nothing here is an invitation to enter into a loan. If any borrowing would be secured on your own home (for example bridging a residential chain, or a regulated mortgage), that is a regulated product outside the scope of this guide, and you should speak to an FCA-authorised mortgage adviser. To estimate the finance itself, our development finance calculator models loan to GDV and loan to cost as information, not an offer.

Where we help is the tax. The single most valuable thing to get right on a development is the trading-versus-investment classification, because it decides your interest relief, whether Section 24 bites, whether the profit is income or a gain, and how the finance fees and VAT are treated. If you are financing a scheme and want the tax treatment settled before you draw the facility, ask us for a property development tax review using the form below. We look at your intended structure, your finance and your exit, and tell you how HMRC will see it, in writing, before it becomes a problem in an enquiry.