Landlords who rushed to buy houses earlier this year are starting to lease them out, offering renters with a flood of properties, research recommends.
A record number of sales happened in March, as purchasers tried to beat last month's Stamp Duty deadline.
That has led to an 11.5% increase in rental properties being noted in April, according to data from the website Rightmove.
Some locations, like Worcester, have actually seen rental listings surge by almost 50%.
Even in London, the number of houses for lease increased by 9.1% last month, states the research performed by investment firm Property Partner.
It looked at 90 towns and cities throughout the UK, and found that the supply of properties went up in 82% of them.
Many property managers might take some time to refurbish their newly-acquired houses, before offering them for rent.
" Some proprietors may wish to do up their properties - such as getting the painters in, or setting up a brand-new kitchen area - so there may be a hold-up," said Richard Donnell from the property site Hometrack.
" However, over the next one or two months, a sensible slug of these properties will come on the marketplace."
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In theory, increased supply should imply a fall in the expense of leasing.
However according to the Reed Rains buy-to-let index, rents have been falling in any case since September 2015.
At that time, leas in England and Wales hit an average of 816 a month. By April 2016 they had fallen to 791 a month.
Adrian Gill, a director of Reed Rains and Your Move, thinks they will not fall much further.
" Tenants still need houses and need is still rising," he told the BBC.
" So actually later on in 2012 the balance of supply and need may move even further in favour of landlords. A short-term spurt of supply won't shift the basics."
Dan Gandesha, the chief executive of Property Partner, stated the supply of rental properties was unlikely to continue increasing.