| 1849 | Harding & Pullein founded in England. Joined by Frederick Whinney |
| 1859 | Whinney made a partner |
| 1894 | Arthur Young starts his first firm, Stuart and Young, in Chicago
Harding & Pullein renamed Whinney, Smith & Whinney |
| 1864 | Thomas Clarkson starts a trustee and receivership firm in Toronto |
| 1903 | Alwin and Theodore Ernst form Ernst & Ernst in Cleveland, US |
| 1906 | Arthur and brother Stanley form Arthur Young & Company in Chicago |
| 1924 | Arthur Young allies with Broad Paterson & Co, England
Ernst & Ernst allies with Whinney, Smith & Whinney |
| 1939 | Clarkson allies with Woods Gordon & Co to expand into management consulting |
| 1944 | Clarkson Gordon & Company allies with Arthur Young & Co |
| 1979 | Ernst & Whinney forms and becomes the fourth largest accountancy firm in the world
Arthur Young’s European offices join several large local European firms |
| 1989 | Arthur Young merges with Ernst & Whinney to create Ernst & Young |
| 2000 | Ernst & Young unveils a new, integrated global organization |
