In a move for which the UK equivalent would be Rightmove acquiring Zoopla, giant American property portal Zillow has announced its purchase of heavyweight rival Trulia.

It is paying $3.5bn (approx £2bn). The transaction will be all in stocks, and is expected to complete next year.

The combined company will operate the two brands separately, but Trulia’s CEO Pete Flint will report to Zillow’s CEO Spencer Rascoff.

Rascoff said: “Consumers love using Zillow and Trulia to find vital information about homes and connect with the best local real estate professionals.

“Both companies have been enormously successful in creating compelling consumer brands and deep industry partnerships, but it’s still early days in the world of real estate advertising on mobile and web.

“This is a tremendous opportunity to combine our resources and achieve even more impressive innovation that will benefit consumers and the real estate industry.”

Flint said: “By working together, we will be able to create even more value for home buyers, sellers, and renters, as well as create a robust marketing platform that will help our industry partners connect with potential clients and grow their businesses even more efficiently.”

Efficiencies are likely to lead to savings of at least $100m a year.

In June, Zillow reported a record 83m users, while Trulia reported a record 54m.

The two brands claim there is limited overlap of visitors, with around half of Trulia’s visitors not going on Zillow, and about two-thirds of Zillow’s traffic not visiting Trulia.

A joint statement said: “Maintaining the two distinct consumer brands will allow the combined company to continue to offer differentiated products and user experiences, attract more users and maximize the distribution of free content across multiple platforms, apps and channels.”