Cushman & Wakefield and DTZ say they will combine in a deal creating one of the world's largest real estate companies.

Exor SpA, an Italian investment firm that owns most of Cushman & Wakefield, said Monday that DTZ will buy Cushman for $2.04-billion.

The two privately-held companies say that together, they will have $5.5-billion in annual revenue and manage more than 4 billion square feet of real estate.

Story continues below advertisement

The companies expect to complete the deal before the end of 2015. The combined company will be called Cushman & Wakefield, and it will have about 43,000 employees.

Exor said it will get $1.28-billion in net proceeds from its part of the sale.

Chicago-based DTZ was acquired by TPG Capital, PAG Asian Capital, and the Ontario Teachers' Pension Plan in November. It focused on international real estate at the time. Two months later they acquired U.S.-based Cassidy Turley and then combined the two companies.

Cushman & Wakefield is based in New York. It was founded in 1917 and is one of the world's largest commercial real estate firms.

Story continues below advertisement

Exor is controlled by the Agnelli family, the descendants of the founder of Fiat. According to FactSet, it is the largest investor in both Fiat Chrysler Automobiles NV and CNH Industrial NV, Fiat's former agriculture and construction equipment business. The company is also trying to buy reinsurance company PartnerRe Ltd., which has rejected its offers and says it plans to go through with a previously-announced merger with Axis Capital Holdings Ltd.