HMO yields and lender affordability tests

Yield is the annual income a property produces expressed as a percentage of its value or cost, and there are two versions that are easy to confuse.

Gross yield is the headline figure. You take the total annual rent and divide it by the property value or purchase price, then multiply by a hundred. It is quick to work out and useful for comparing properties at a glance, but it ignores every cost of running the place, so it flatters an HMO in particular.

Net yield is the honest figure. You take the annual rent, subtract the real running costs, and divide that net income by the value or total cost. Because HMOs carry heavier costs than single lets, the gap between gross and net is wider than many landlords expect.

• Gross yield: annual rent divided by value, before any costs.
• Net yield: annual rent less running costs, divided by value or total cost.

HMOs typically show attractive gross yields because several rooms each pay rent, but the net yield is what tells you whether the property actually makes money after bills, voids and management. When you assess a deal, and when a lender assesses it, the net position is what matters, so it pays to work in net terms from the start.

Working out an HMO yield is a matter of building the income up room by room, then stripping out the costs a shared house genuinely carries.

Start with the gross rent. Multiply the number of lettable rooms by the achievable rent per room, then annualise it. A six bed HMO where each room lets for a set monthly figure produces six times that rent every month, which is the reason HMO gross income looks strong next to a single let.

Next, allow for voids. Rooms sit empty between tenants, and in an HMO with many rooms there is almost always some turnover, so it is realistic to assume the property is not one hundred percent let all year. Reducing the gross rent by a sensible void allowance gives a figure you can actually rely on.

Then deduct the running costs, which on an HMO are substantial.

• Utility bills: in most HMOs the landlord pays gas, electricity, water and broadband, since rooms are usually let inclusive of bills.
• Council tax: often a landlord cost, depending on the property and local rules.
• Management and maintenance: shared houses need more hands on management and wear more heavily than single lets.
• Licensing, insurance and safety: HMO licence fees, specialist insurance and regular safety checks all add up.

Subtract those costs from the rent after voids to reach net income, then divide by the property value or your total cost to get the net yield. That single figure tells you whether the deal works, and it is the number worth stress testing before you commit, because an optimistic rent or a forgotten cost can turn a strong looking HMO into a thin one.

When a lender assesses an HMO loan, they are not just checking the yield. They run a rental stress test to make sure the rent comfortably covers the mortgage interest, even if rates were higher than they are today. The tool they use is the interest cover ratio, or ICR.

The ICR is the rental income expressed as a percentage of the mortgage interest, calculated at a stressed interest rate rather than the actual pay rate. In plain terms, the lender wants the rent to exceed the interest by a healthy margin, so the loan stays affordable if borrowing costs rise. A typical requirement is that rent covers interest by 125% to 145%, and where a case sits in that band depends largely on the borrower's circumstances and the product.

• Lower end, around 125%: often applied to limited company borrowers and basic rate taxpayers, where the tax treatment of interest is more favourable.
• Higher end, around 140% to 145%: often applied to higher and additional rate taxpayers borrowing personally, to allow for the tax they pay on rental profit.

The lender also chooses a stress rate, the notional interest rate the test is run at, which is usually set above the actual product rate, though longer fixed rates are sometimes stressed more gently. The combination of the required ICR percentage and the stress rate is what the rent has to satisfy. Because HMOs produce strong rents, they often pass comfortably, but a property with weak room rents or heavy voids can fail the test even when the headline yield looks fine. On tax matters, speak to a qualified accountant, since the treatment affects which ICR band applies to you.

The ICR does more than pass or fail a deal. It often sets the ceiling on how much you can borrow, and on HMOs it is frequently the binding constraint rather than loan to value.

The logic runs backwards from the rent. The lender takes your achievable rent, applies the required ICR and the stress rate, and solves for the largest loan whose stressed interest the rent can still cover at that ratio. A higher rent supports a larger loan, a tougher ICR or a higher stress rate shrinks it. In practice, a lender might approve up to the loan to value ceiling, with HMO loan to value typically running up to around 70% to 75%, but only if the rent clears the ICR test at that level. If it does not, the affordability calculation caps the loan below the loan to value limit.

This is why two borrowers buying the same HMO at the same price can be offered different loan sizes. A basic rate or limited company borrower stressed at 125% can often borrow more against the same rent than a higher rate taxpayer stressed at 145%, because the rent has to stretch further for the latter. It is also why the rent roll deserves careful attention. Pushing achievable room rents higher, or trimming voids, feeds straight through into borrowing capacity. Rates across HMO mortgages sit broadly in the 5.5% to 6.5% band, indicative and subject to status and valuation, and the pay rate, stress rate and ICR together decide the number you walk away with.

Sometimes a borrower wants a larger loan than the rent will support on the ICR test alone. This is where top slicing can help. Top slicing is where a lender allows you to use surplus personal or portfolio income to make up the shortfall between what the rent covers and the loan you want, provided you can evidence that income comfortably.

In practice, if the rent covers the interest at say 120% but the lender needs 125%, a borrower with clearly demonstrable surplus earnings may be able to bridge that gap, because the lender can see the affordability is met from a wider view of your finances rather than the rent alone. It is most useful for lower yielding areas, for higher rate taxpayers facing a tougher ICR, or where a borrower deliberately wants to gear a little higher on a property they are confident in.

Top slicing is not universal. Not every lender offers it, those that do apply their own rules on the type and amount of income they will count, and it depends on you having genuine surplus income to draw on. It should also be used thoughtfully, since it lets you borrow more than the rent alone would justify, which raises your exposure if circumstances change. As brokers we can identify which lenders top slice and how they treat different income sources, so if the rent falls a little short of your target loan, there may still be a route through. These figures are indicative bands only, subject to status and valuation, and regulated cases are referred to an authorised firm. Nothing here is financial, legal or tax advice.

Yield and affordability are two sides of the same rent roll, and the strongest HMO cases satisfy both. Yield tells you whether the property is worth owning, the return you earn after real costs. Affordability tells you whether a lender will fund it, and how much they will advance. A property can show a healthy net yield yet still be capped by the ICR test, and a property can pass affordability easily yet deliver a thin net return once every cost is counted. You want both to work.

The practical takeaway is to model the deal in net terms and to think like a lender from the outset. Build the rent room by room, apply a realistic void allowance, deduct the full running costs, and then check how that rent performs against a stressed interest rate at the ICR your circumstances attract. If the numbers are tight, that is the moment to look at whether stronger room rents, a different lender, or top slicing changes the picture, rather than discovering the shortfall late in the process.

Every HMO is different, and the right structure depends on your tax position, the property and your wider portfolio, so it is worth talking a specific case through. We are happy to work through the yield and affordability on a property you are considering and point you to lenders whose ICR and stress approach fit. These are indicative bands only, subject to status and valuation, and nothing here is financial, legal, planning or tax advice.