Buy-to-let landlords have driven a massive shift in the property market that has taken a million homes out of residential ownership in a decade.
Since 2005, an extra one million homes are now occupied by a tenant rather than homeowner.
Countrywide, which conducted the research, said amateur landlords and other property investors make formidable competition for those trying to buy a place of their own.
Two million homes have changed tenure in the last decade, either switching from home owners to landlords or vice versa.
The rapid growth of the private rented sector over the last 10 years means that one million homes occupied by the owner in 2005 are now owned by a landlord.
This makes up half of the growth in rented stock in that time.
The rest of the increase in the number of rented properties has come from landlords buying newly-built homes and to a lesser extent conversions and ex-social housing.
Some 700,000 new homes built since 2005 have found their way into the private rented sector.
In the last decade, 1,550,000 properties have gone from owner-occupied to rented, while 550,000 have moved from the private rented sector into owner occupation.
Some 45,000 first-time buyers bought their home from a landlord in the last year, 15% of all first-time buyer sales, the highest number since the market downturn in 2008
First-time buyers buy 65% of the homes that leave the private rented sector.
With first-time buyers and landlords tending to look for homes which are smaller and cheaper than average, they often find themselves in competition. As a result, both groups are disproportionately likely to sell homes to one another.
Johnny Morris, director of research at Countrywide said: “The rapid growth of the private rented sector has to come from somewhere.
“The sector has been growing since 2005 but the number of homeowners has fallen in each of the last 10 years.
“This scale of shift in tenure shows that the current push from the government to increase the number of homeowners is unlikely to be enough to reverse the decline."