Zoopla's latest figures suggest 70,000 transactions are likely to miss the stamp duty holiday deadline of March 31.
And the portal says: “The case is growing for a short, month long extension to help buyers who agreed a sale in 2020, and secure the expected savings.”
In its latest market analysis Zoopla says with so many sales agreed in the second half of last year, and now racing to beat the cut off date, the average time for a sale to complete is over the usual three months and closer to four months.
It says that in a normal year, around 55 per cent of sales agreed in January would complete by the end of the first quarter - the proportion this year is likely to be lower.
What is not clear, it says, is how many individual sales and housing chains are 100 per cent dependent on securing the stamp duty savings.
“The more buyers rely on securing savings, the greater risk of a spike in sales falling through, with a knock-on impact for whole chains of sales. If an extension fails to materialise, buyers across some chains may help to fund stamp duty costs for others in the chain to safeguard completions” says the portal’s report on the market.
In its general assessment of the market, Zoopla notes that recent record Covid cases and calls to uphold social distancing and other restrictions have deterred some sellers.
It says that in the first weeks of 2021, the flow of new homes coming to the market for sale was 12 per cent lower than a year ago.
“By contrast, buyer demand for property has rebounded after the Christmas break - growing even faster than at the start of 2020. In the period to the 17 January, demand for homes is 13 per cent higher than the same period a year ago when the market had started to rebound in the wake of the General Election. New sales agreed are also running eight per cent higher than last year” it notes.
Richard Donnell, the portal company’s research and insight director, says: “Sellers are more cautious however and appear to be waiting for [Coronavirus] case numbers to drop much further before listing their home, or until we see a return to tier based restrictions.
“The strength of the market in 2020 has eroded the available number of homes for sale and this will mean continued upward pressure on house prices in the short term.
‘The most affordable parts of the UK are recording the highest rate of price growth for 10 years up to 5.4 per cent a year. We still expect house price growth to slow towards 1.0 per cent by the end of the year.
“The rush to beat the stamp duty deadline continues and sellers who agreed to buy a home in 2020 would reasonably expect to make the stamp duty saving. Delays mean we expect up to 70,000 sales agreed in 2020 to miss the deadline meaning the case for a short extension is growing.”