TwentyCi Q3 2026 data reveals high value homes take twice as long to sell as the broader market
Only one in four high value homes priced above £2m that reached an outcome in Q3 2026 went on to sell. That figure carries weight for mortgage lenders working through the possible impact of the incoming High Value Council Tax Surcharge.
The findings are drawn from TwentyCi’s Property & Homemover Report for Q3 2026. They show a residential market far more fragmented by price and property type than national averages suggest.
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High-value homes: longer waits, lower returns
Only one in four £2m-plus homes that concluded a transaction in Q3 changed hands, against a 53.1% sale rate for properties priced below that threshold. At the top end of the market, the typical property took 86 days to find a buyer compared with 41 days across the broader sub-£2m segment. When sales did complete, high-value homes achieved 90.5% of their initial asking price, against 96.3% for lower-priced properties.
TwentyCi notes that the 90.5% figure is based on 27 completions in the quarter and should be treated as indicative rather than conclusive.
The High Value Council Tax Surcharge (HVCTS) — widely referred to as the mansion tax — was confirmed in Rachel Reeves’ Autumn Budget in November 2025. It takes effect in April 2028. Properties in England valued above £2m will face annual charges of between £2,500 and £7,500, depending on value band, based on 2026 valuations.
The Office for Budget Responsibility has said it expects the full cost of the surcharge to be reflected in property prices over time, with full pass-through assumed from 2028–29 onwards. That means a property’s market value is likely to adjust downward to account for the recurring annual liability. Lenders holding high value homes as security will need to weigh this alongside conventional valuation.
Flat sales: a separate structural problem
The national picture for flats is deteriorating. Just 41.2% of those listed were expected to sell in 2026, a decline from 44.2% the previous year and well below the 54.2% recorded in 2022. London was the weakest regional market, with Inner London recording a projected sale rate of just 27.2% and Outer London only marginally better at 30.7%.
These figures compound a longer-running set of structural pressures. Flat prices in England rose just 16% over the decade to February 2026. That compares with 40.9% growth for detached homes over the same period. That widening gap is reshaping remortgage and lending conversations across the flat market.
Fire safety concerns stemming from the post-Grenfell period continue to cast a shadow over parts of the flat market. While EWS1 forms are not a legal requirement, their use has fallen considerably from its peak. Some lenders still request them on certain buildings, adding friction to transactions and valuations.
What do falling sale rates mean for mortgage lender security?
Colin Bradshaw, chief executive of TwentyCi, said the research reinforced the limits of headline market data for lending decisions. “The housing market cannot be understood through headline transaction volumes or average property prices alone,” he said.
“Our latest research highlights how sharply the likelihood and speed of a sale can vary, with flats facing increasing challenges and properties at the top end of the market taking considerably longer to find buyers.”
Bradshaw added that granular, property-level insight was becoming more operationally significant. “A valuation provides an essential benchmark, but insight into current supply, demand and selling times can add another valuable dimension to understanding the risks associated with a property,” he said.
Understanding how long a high-value property is likely to sit on the market is increasingly relevant to refinancing conversations. So too is the achievable price relative to the asking figure.
The data does not categorise flats or high-value homes as unsuitable security. It does make a case for looking beyond static valuations toward current conditions in the specific local market and property type.
TwentyCi’s report analyses the UK residential property market using data covering 99.6% of sale and rental transactions.
