OnTheMarket has recruited high-profile London firm Portico.
The business has 17 branches and is now listing at OTM.
Mark Lawrinson, Portico’s regional director, said: “We are really excited to join OnTheMarket and to see where this new partnership takes us.”
Helen Whiteley, commercial director at OnTheMarket, said: “We’re thrilled to see this prestigious firm join at this exciting time for the portal.
“Since our admission to AIM in February, other large firms including Arun, Belvoir, Chancellors, Hunters, Townends, Andrews and Pattinson have all decided to list all their properties at OTM, along with thousands of other smaller firms which have helped generate momentum in local marketplaces across the UK.
“The more agents who join us now, the more we believe all agents and property-seekers will benefit in terms of the increased property stock at OTM.
“We remain committed to creating an agent-backed, full scale challenger portal.”
OTM now has over 11,500 branches listing with it – more than twice the number listing at the time of the company’s flotation on February 9.