EY operates as a network of member firms which are structured as separate legal entities in a partnership, which has close to 300,000 employees in over 700 offices in more than 150 countries around the world. The firm's current partnership was formed in 1989 by a merger of two accounting firms; Ernst & Whinney and Arthur Young & Co. It was named Ernst & Young until a rebranding campaign officially changed its name to EY in 2013, although this initialism was already used informally prior to its sanctioning adoption.