In the three months after the introduction of the three per cent stamp duty surcharge on April 1, landlord purchases accounted for only eight per cent of all homes bought - the lowest proportion since 2010.
This comes following the surge in activity in the first quarter of the year, where landlords accounted for 18 per cent of home buyers, the highest proportion seen since 2010.
The largest change in landlord activity was in the North, Midlands and Wales.
In the North East, after 29 per cent of homes sold were bought by landlords in the first quarter of 2016, this plummetted to nine per cent in the second quarter.
Similarly, in Wales and the East Midlands, this fell from 19 per cent to three per cent and 22 per cent to eight per cent respectively.
The increased purchase activity from landlords at the start of 2016 has led to the number of homes available to rent increasing by 22 per cent in June compared to last year.
London and the South West have seen the largest growth in homes available to rent, the number rising by 33 per cent and 55 per cent respectively.
Increasing supply, as well as affordability barriers, has reduced the rate of rental growth with most regions seeing slower growth rates throughout the year.
The average rent across Britain rose to £960 in June, 3.6 per cent higher than last year.
“The lull in landlord activity is mostly due to investors bringing forward purchases in the first three months of the year but upcoming changes to mortgage tax relief and the prospect of heightened uncertainty in economy during the lead up to the referendum, will also have made investors warier of entering the market” says Johnny Morris, research director at Countrywide.
“Those extra homes bought by landlords at the start of the year are still making their way to market. Despite tenant numbers still growing, the increased supply is slowing rental growth.”