The UK’s largest online property platform, Rightmove, is bracing for an “imminent” £1 billion ($1.31 billion) class action lawsuit, with thousands of estate agents accusing the FTSE 100 company of charging excessive and unjustified fees that exploit its market dominance.

The proposed opt-out claim, announced Thursday, is spearheaded by Jeremy Newman, an accountant and former member of the Competition and Markets Authority (CMA). He alleges that Rightmove has abused its dominant position in the online property listings market, effectively cornering estate agents into paying inflated subscription costs.

Profit Margins That Raise Eyebrows

Newman’s filing points to Rightmove’s astonishing 70% profit margin, branding it the most profitable company on the FTSE 100. The platform serves as the UK’s central hub for estate and letting agents, as well as developers listing properties for sale or rent.

“Rightmove knows that, thanks to its first-mover advantage, its product is viewed as a ‘must-have’ for estate agents,” Newman stated. “It exploits this dominance to impose unfairly high subscription fees, both outright and in comparison with its rivals.”

The complaint alleges that estate agents have been forced to shoulder regular and steep price hikes, with few viable alternatives due to Rightmove’s overwhelming grip on the market.

A Battle to Level the Playing Field

Backing the lawsuit, Ian Garrard, managing director of Innsworth Advisors, the advisory firm to the case’s litigation funder, said the claim aims to “level the playing field for businesses up and down the country.”

“This is about deterring anti-competitive behavior and correcting the imbalance between big and small players in the property sector,” Garrard added, emphasizing that smaller agents have long been at a disadvantage in negotiations with the portal giant.

Rightmove’s Response: Defiant Confidence

Rightmove confirmed Thursday that it had received notice of a potential class action, but expressed confidence in its position. “We’re confident in the value we provide to our partners,” a company spokesperson said.

The platform, which dominates the UK’s digital real estate landscape, has long been viewed as indispensable for agents, a status that now stands at the center of the legal storm.

The Legal Team and What Comes Next

Newman is being represented by Kieron Beal KC of Blackstone Chambers, instructed by Scott+Scott UK LLP, a firm known for leading major competition law claims.

Counsel information for Rightmove has not yet been disclosed.

If successful, the lawsuit could reshape the financial dynamics of the UK’s property sector, marking one of the largest competition claims in British history—a showdown that pits thousands of small agents against one of the market’s most powerful players.