Some 12 per cent of transactions in England and Wales so far this year have been subject to gazumping, being sold at at least one per cent higher than that agreed at the point of Sold Subject To Contract.
Consultancy TwentyCi says Greater London has seen the greatest level of gazumping, with 14.46 per cent of property transactions affected.
Next up was the West Midlands with 13.97 per cent of transactions, while the South West and Wales have seen the lowest rates of properties being gazumped at nine per cent and seven per cent respectively.
In addition to looking at the percentage of gazumped properties, TwentyCi monitored the levels of gazumping throughout the first three quarters of 2017 to identify which regions had seen the largest movements in the practice.
Across England and Wales overall, there has been a general increase in the rate of gazumping as the year has progressed, rising from 10 per cent of properties in the first three months of the year to 13 per cent in the third quarter.
The data used by TwentyCi for this analysis covers 99.6 per cent of the UK home mover market and includes the period from January 2017 to August 2017 inclusive.
The government specifically identified gazumping as a problem in the house buying process that it wished to stamp out in its reforms; a call for evidence was made by the Department of Communities and Local Government almost a fortnight ago.