The firm as we know it today is the result of a series of mergers of ancestor organizations. The oldest originating company was founded in 1849 in England as Harding & Pullein. In that year the company was joined by the American Frederick Whinney. He was made a partner in 1859 and with his sons in the business it was renamed Whinney, Smith & Whinney in 1894. In 1903, the firm of Ernst & Ernst was established in Cleveland by Alwin and Theodore Ernst and in 1906 Arthur Young & Company was set up in Chicago.
In 1965, Whinney, Smith & Whinney merged with Brown, Fleming & Murray to form a accounting and consultancy firm named Whinney Murray. Whinney, Smith & Whinney had been closely allied with Ernst & Ernst since the 1940s and in 1979 Whinney Murray, Ernst & Ernst, and Turquands Barton Mayhew join together as Ernst & Whinney, creating the fourth largest accountancy firm in the world. In 1989, the number four merged with the then number five, Arthur Young, to create Ernst & Young.
The partnership built up its consultancy arm heavily during the 1980s and 90s. The SEC and other members of the investment community began to raise increasing concerns about potential conflicts of interest between the consulting and auditing work. Ernst & Young was the first of the Big Five Auditors to formally and fully separate its systems integration and auditing practices. In May 2000, the consulting arm was sold to the French IT services company Cap Gemini for $11 billion in cash and stock, creating the new consulting firm of Cap Gemini Ernst & Young (CGE&Y).