Guinness Mahon was an Irish merchant bank originally based in Dublin but more recently with operations in London. History Formation The firm was founded as a land agency in Dublin in 1836 by barrister Robert Rundell Guinness, a great-nephew of the brewer Arthur Guinness, and John Ross Mahon, an estate agent. London business A London office opened in 1873, closed in 1916 during World War I and then re-opened again in 1923. In 1939 certain banking business of London Merchant Bank Ltd. (established in 1873) was acquired followed by the current business of Goschens & Cunliffe (established in 1814) in 1941. The London business became Guinness Mahon Holdings, which merged with Lewis & Peat Ltd in 1974, forming Guinness Peat. The firm decided to enter the securities market buying White & Cheesman, a stock jobber, in April 1984. The Group ran into difficulties in the late 1980s and demerged into three parts: the Guinness Mahon investment banking business, Fenchurch Insurance and the off-shore investment activities. The offshore investment activities in Australia and New Zealand (then known as Guinness Peat Group) were bought by Brierley Investments Limited (a business controlled by Sir Ron Brierley) in 1990 and the Guinness Mahon investment banking business was acquired by Bank of Yokohama in 1991 and then sold on to Investec in 1998. Meanwhile, Fenchurch Insurance merged with Lowndes Lambert in 1997 to create Lambert Fenchurch, then with Heath Group in 1999 to form Heath Lambert and then with Arthur J. Gallagher & Co. in 2011 to form Gallagher Heath. Irish business From April 1986 to August 1994, Guinness & Mahon (Ireland) Ltd was a wholly owned subsidiary of Guinness Mahon & Co., London. The bank's Irish private banking operation was acquired by Irish Permanent on 31 August 1994, and operated from a single location. The operations acquired were scaled down in 2000. There were also companies associated with Guinness & Mahon (Ireland) Limited and Guinness, Mahon & Co., London, who placed deposits with Guinness & Mahon (Ireland) Limited. These companies were - Guinness, Mahon (Guernsey) Limited, College Trustees Limited, Guinness, Mahon Jersey Trust Limited, Overseas Nominees Limited and subsidiaries of Credit Suisse. Operations Its subsidiaries and offshoots included Guinness Peat Aviation and Guinness Peat Group in Australia and New Zealand and Guinness Flight Hambro, which became Investec Guinness Flight. References Further reading Former investment banks 1836 establishments in Ireland Banks established in 1836 Banks