Asking and agreed rents continued to outpace incomes with tenants spending 28.3% of their pre-tax earnings on rent last month, above the 10-year average of 27%, Zoopla said.
May's figures marked the 19th month in a row that rental price growth outstripped incomes.
He expected affordability strains to slow the pace of rental growth in 2024.
Inflation data for May is due to be published on Wednesday.
Zoopla said 53% of renters it surveyed reported a rent rise in the six months to May, up from 35% six months earlier.
Persons:
Toby Melville, Zoopla, Richard Donnell, Donnell, BoE, Moneyfacts, Liz Truss's, Zoopla's Donnell, Zoopla's, Suban Abdulla, Christina Fincher
Organizations:
REUTERS, Homeowners, Bank of, Nationwide, HSBC, Halifax, Thomson
Locations:
London, Britain, Bank of England