An analysis of estate agencies in 21 major cities suggests a big rise in competing companies, prompting risks of fee wars between competitors.
The analysis shows that the number of agencies operating within the cities increased by 7.1 per cent on this time last year.
Bristol has seen the biggest uplift at 16 per cent; Bournemouth is up 13 per cent with Southampton, Leeds and Sheffield close behind.
Just two cities have seen a decline in the number of agents - Portsmouth and Aberdeen, down 13 and eight per cent respectively.
The research shows that across these 21 major cities, there is an average of 23 properties listed on the market for every one agency branch, down from 26 per agent this time last year.
Leeds has seen the greatest decline with nine fewer homes listed per branch.
Despite seeing an annual drop of two listings per branch, Liverpool remains the busiest with 39 properties on the market per branch.
Cambridge is home to the fiercest level of competition, with just 12 properties listed for every one branch.
The research has been commissioned by Nested, an online agency which has been running a campaign to woo traditionally-employed agents over to self-employed status.
Nested spokeswoman Alice Bullard says of the increase in agency branches: “This means more competition and a lower number of homes per agent on average, which inevitably results in a drop in revenue for those who can’t differentiate themselves from the rest of the market.
“For those big brand names with a hefty wage bill and multiple branches to support, this could spell trouble, particularly in the cities that have seen the biggest increase in competition.
“However, those that have made the choice to follow the self-employed route with the support of a trusted brand are far better placed to negotiate a more competitive marketplace.”