The average landlord sold selling a buy to let last year made a gain of almost £80,000, according to new data.
The biggest profits were in London, where landlords scooped an average £248,000 gain.
But while 85% of landlords managed to sell for an impressive gain after owning a rental property for an average 9.6 years, one in six (15%) sold at a loss.
The average gain for landlords across England and Wales was £79,770 before capital gains tax, says the data from property consultancy Hamptons International.
However, the figure is 4.4% lower than the average gain of £83,430 posted the year before.
Although gains were higher in the capital, they were still £24,000 lower than in 2017.
The data showed that investment properties were likely to make a smaller gain or sell at a loss the farther they were from London.
Landlords in the North-East enjoyed an average gain of just £11,810 – down £4,270 from 2017, but only 56% sold at a profit and the four worst performing buy to let local authority areas are all in the region.
The percentage of properties sold at a loss numbered 49% in South Tyneside, 48% in Sunderland, 45% in Darlington and 43% in Middlesbrough.
The biggest profits in London were in Kensington & Chelsea (£1.072 million), while South Buckinghamshire posted the largest gains outside the capital (£278,310).
Aneisha Beveridge, head of research at Hamptons International, said: “The average landlord who sold their buy-to-let last year did so for nearly £80,000 more than they paid for it. Over the 9.6 years that the average landlord has owned their buy-to-let, house price growth has driven their gains, with prices having risen around 30% over the period.
“But given lower expected future house price growth and tighter mortgage regulation, more investors are shifting their focus from capital gains to yields.”