By the UKPropertyCalculator team • Published 24 August 2026
Every shared ownership brochure I've read leads with the same headline: "own your home from just a 5% deposit on a 25% share." What none of them lead with is that you're also paying rent, a service charge, and a rent review clause that lifts your bill every year. There are now around 252,000 shared ownership households in England — up from 161,000 five years ago — and a lot of them signed up with only half the numbers in front of them. This piece is the other half.
You buy a share of a property — typically between 25% and 75%, with a 10% minimum share available on homes delivered under the 2021 model — and pay rent to a housing association on the share you didn't buy. Your mortgage covers only the share you own. The rest is treated as a subsidised tenancy. Every shared ownership home is leasehold, and under the 2021 model the lease runs for 990 years, up from 99 or 125 years on older schemes.
To qualify, your household income must be under £80,000 across England, or under £90,000 in London. You can't already own another home, and you have to show that a full-market purchase is out of reach. Beyond that, the scheme is open to first-time buyers, former owners who can no longer afford to buy, and people forming new households.
The pitch is genuine as far as it goes. If you have £8,000 rather than £32,000 saved, shared ownership is often the only route to any form of ownership on a property that size. The trap is that the monthly cost isn't as low as the deposit reduction implies — and the rules that surround your share are stricter than a standard leasehold buyer ever has to think about.
Under Homes England's Affordable Homes Programme, the rent on the unsold share is capped at 3% of that share's value per year. In practice most providers set the opening rent below the cap, commonly around 2.75%, so that is the figure used throughout this article. That "subsidised" rent is meaningfully below market rate — a market let of the same flat might run at 5–6% of full property value — but on the share you don't own, the maths still stings.
Take a £320,000 home with a 25% share. You've bought £80,000 of property. The housing association still holds £240,000. Rent at 2.75% comes to £6,600 a year, or £550 a month, and that's before your mortgage and before your service charge. It's not a token payment. It's the largest single line on most shared ownership monthly budgets.
Every shared ownership lease has a rent review clause. Under the 2021 model lease, from 12 October 2023 onwards, the formula is CPI + 1% per year. Leases granted before that used RPI + 0.5%, which produced eye-watering increases when RPI ran hot in 2022 and 2023 — some shared owners saw double-digit rent hikes on top of everything else that year. The switch to CPI-based reviews cuts the volatility a bit, but it doesn't cap the rise.
Take that £550 opening rent. If CPI runs at 2% for the next decade, your rent goes up by 3% every year. After ten years you're paying £738 a month instead of £550 — nearly £190 extra, and it keeps compounding. If CPI spikes above 3% for a couple of years, as it did in the early 2020s, the effect is sharper. Wages haven't tracked that pace, so the share of your income going to the housing association tends to grow over time.
The mortgage on the share you own is optional to fix or track. The rent, by contrast, will rise every year regardless of what your salary does or what happens to interest rates. Build the annual increase into your budget from day one — most shared owners don't, and they find themselves squeezed by year three or four.
Every shared ownership property comes with a service charge, because every shared ownership property is leasehold and almost all are flats. That charge covers block maintenance, buildings insurance, communal cleaning, lift servicing, and any managing agent fees. The range is the same as for any leasehold flat: £1,200 a year at the low end, £3,000–£5,000 for a modern block with lifts and concierges, and occasional five-figure section 20 major works bills on top.
The awkward truth is that you pay the full service charge, not 25% of it. Your 25% share buys you full occupation of the property, so you're responsible for the property's full running cost. The housing association doesn't chip in on the basis that it still owns 75% of the bricks. There are reforms coming through the Leasehold and Freehold Reform Act 2024 to strengthen leaseholder rights over service charge transparency and challenge, but the underlying bill is still yours in full — see our leasehold vs freehold cost guide for how those charges work in practice.
The 2021 model lease introduced something genuinely helpful: for the first ten years, the housing association contributes up to £500 per year towards essential repairs to walls, floors, stairs, ceilings and other structural items inside your home. Any unused allowance rolls forward, so if you don't claim in year one, you have £1,000 available in year two.
It's a real improvement on the older model, where all internal repair costs fell on the shared owner from day one regardless of what share they held. But read the scope carefully. The £500 covers essential structural repairs. It doesn't cover redecoration, ordinary maintenance, or replacement of white goods and boilers that fail from wear and tear. A new boiler at £2,500 is your bill, not the housing association's, even in year three of ownership.
After the ten years, the repair contribution ends entirely. From year eleven you're on the same footing as any other leaseholder inside the flat, still paying the service charge for anything outside it.
Say you're looking at a £320,000 flat. Shared ownership offers a 25% share at £80,000 with a 10% deposit on that share (£8,000). Compare that to buying the same flat outright at 10% deposit (£32,000). Same mortgage rate (4.5%, 25-year term), same service charge (£150 a month), same starting point.
| Monthly line | 25% shared ownership | Full ownership |
|---|---|---|
| Deposit (day one, cash) | £8,000 | £32,000 |
| Mortgage payment (25-yr, 4.5%) | £400 | £1,601 |
| Rent on unsold 75% (2.75%) | £550 | £0 |
| Service charge | £150 | £150 |
| Total monthly outgoing (year one) | £1,100 | £1,751 |
| Rent review (CPI + 1%, roughly 3%/yr) | Rises every year | — |
| Equity built after year one | ~£1,600 (share only) | ~£6,400 |
Shared ownership genuinely saves you £651 a month in year one, and it wants only a quarter of the deposit. That's why it works for people who couldn't otherwise buy. But you're building equity on £80,000 of property, not £320,000. And the rent line — which builds nothing — rises every year while the mortgage line stays fixed if you refix well.
Model your own numbers against the alternative in our Buy vs Rent Calculator. The one line the calculator doesn't automatically add is the shared owner's rent; if you're comparing shared ownership to a straight rent, treat the shared owner's total monthly outgoing (mortgage + rent + service charge) as the "buy" number and the market rent for the same home as the "rent" number. That's the honest comparison.
Staircasing means buying additional shares of your home over time, moving from 25% to 50% to 75% and eventually — if you want — to 100%. The 2021 model lease changed how this works, and the change matters.
1% gradual staircasing. For the first 15 years of ownership, you can buy 1% at a time using the House Price Index to reprice the share rather than a full RICS valuation. There's typically no valuation fee, and providers under the programme are expected to keep admin fees minimal. Over 15 years you can move from 25% to 40% just by opting in each year. It's the closest shared ownership gets to a pure savings plan.
Standard staircasing in 5% or larger blocks. Anything above 1% at a time (or after the 15-year window closes) needs a full RICS valuation, solicitor fees on both sides, and — if you're funding it with more mortgage — a remortgage. Rough guide: £600–£1,000 for the valuation, £1,000–£2,000 in legal fees, and mortgage arrangement fees on top. Do that four times to get from 25% to 100% and you've paid £15,000–£20,000 in transactional cost that a straight buyer never sees.
Once you reach 100%, the freeholder relationship changes. The rent stops, you're a full leaseholder, and you can sell on the open market like any other leaseholder — service charges, ground rent history and all. Some people call this the "escape velocity" moment. Others reach it only just before selling, using the back-to-back sale route below.
You can't just put a sub-100% shared ownership property on Rightmove and wait for offers. The lease gives the housing association a nomination period — typically 4, 8 or 12 weeks depending on the specific lease — during which they try to find a buyer from their own waiting list who fits the eligibility criteria (income cap, first-time-buyer or equivalent status, and so on).
Any buyer they find takes on your share at a RICS valuation price rather than an offer-and-negotiate price. If they can't find one inside the window, you can then market the property yourself, but any buyer still has to meet shared ownership eligibility — so your pool is smaller than for a standard flat on the same street.
There's a workaround called back-to-back staircasing (or a "SIM sale"). You staircase to 100% at the point of sale — using the buyer's funds — and sell as a standard leasehold flat simultaneously. That opens you to the full open-market buyer pool, but you pay the full transactional stack: RICS valuation, both sides' legal fees, and any provider admin. Whether it makes sense depends on the price gap between a shared ownership buyer and a mainstream buyer for the same flat, which in most markets is a few thousand pounds in your favour.
Read this far and you'd be forgiven for thinking the whole thing is a bad deal. It isn't — for a specific type of buyer.
And it's the wrong call when: your deposit constraint is fixable in 12–18 months of steady saving; you're planning to move within three years; or you're eyeing a property where the service charge is already high and rising. In those cases the mainstream route — save longer, buy less, or accept renting for a bit longer — usually beats the shared ownership monthly on a five-year view.
Homes England's Affordable Homes Programme caps rent at 3% of the value of the unsold share per year; most providers open a little below that, commonly around 2.75%. On a £320,000 home with a 25% share, that's rent on £240,000 — around £550 a month before any annual increase.
Under leases granted or reviewed from 12 October 2023, the formula is CPI + 1%. Older 2021 model leases used RPI + 0.5%, which produced sharper spikes during the 2022–23 inflation window. Either way, the rent rises annually.
Not automatically. Each staircasing transaction in 5% or larger blocks needs a RICS valuation, solicitor fees, and often a remortgage. The 2021 model lease's 1%-a-year route for the first 15 years is the cheap option — anything above that stacks up transactional costs a straight buyer never faces.
Only once you've staircased to 100%. Below that, the housing association gets a nomination period of 4, 8 or 12 weeks depending on your lease to place their own buyer, and any private buyer must still meet the shared ownership eligibility rules. Back-to-back staircasing on sale is the workaround, at the cost of an extra round of fees.
Working out whether shared ownership actually saves you money?
Buy vs Rent Calculator → Mortgage Calculator →Sources: English Housing Survey 2024–25 shared owners fact sheet (household count of 252,000, up from 161,000 in 2019–20); Homes England Affordable Homes Programme capital funding guide (3% maximum rent on unsold share, 990-year lease term, 1%-per-year staircasing for 15 years, 10-year initial repair contribution of up to £500/year); Ministry of Housing / DLUHC rent standard update effective 12 October 2023 (CPI + 1% shared ownership rent review formula, replacing RPI + 0.5%); Leasehold and Freehold Reform Act 2024 (legislation.gov.uk). Figures are indicative and vary by scheme, provider, and property. This article is for information only — see our Disclaimer.