DTZ is buying rival advisory firm Cushman & Wakefield in a $2bn (€1.8bn) deal.
The new company, which will operate under the Cushman & Wakefield brand, will have revenues of more than $5.5bn and 43,000 staff.
The deal will close by the end of the year.
The deal marks the end of an interesting 12 months for DTZ, having been sold for £663m (€913m) in June last year to the Ontario Teachers’ Pension Plan, TPG and PAG Asia Capital.
Brett White, who will take on the role of chairman and chief executive, said the companies had “remarkably complementary skills and reach in different geographies”.
Upon completion of the merger, Carlo Barel di Sant’Albano, current international chief executive at Cushman & Wakefield and head of the EMEA region, will take a senior global leadership role.
John Santora, current chief executive at North America at Cushman & Wakefield, will become COO and chief integration officer.
Tod Lickerman, current global chief executive DTZ, will become president of the company.