NEW YORK (Reuters) - DTZ, a commercial real-estate-services firm backed by private-equity firm TPG, agreed to buy Cushman & Wakefield Inc for US$2 billion, the Wall Street Journal reported on Monday.

The combined company, which will have more than US$5 billion in annual revenue and 250 offices in more than 50 countries, will retain the Cushman & Wakefield name, the newspaper said.

The deal will alter the global commercial-real-estate-services landscape by creating a clear challenger to the two firms that have been dominating the business until now, CBRE and JLL.

Many firms had been vying for the No. 3 spot but none had come close to CBRE with US$9 billion in 2014 revenue and JLL with US$5.4 billion, said the Journal.

The new company will be run by Brett White, former chief executive of CBRE who helped build that firm into the largest in the world.

Last month, Italian holding company Exor, which controls Cushman & Wakefield, said it had received several non-binding expressions of interest for the real-estate services company.

Reuters could not immediately reach Cushman & Wakefield and TPG for comment outside regular business hours.