William Piercy, 1st Baron Piercy CBE (7 February 1886 – 7 July 1966) was a British economist, civil servant, businessman and financier. He is best remembered as chairman of the Industrial & Commercial Finance Corporation from 1945 to 1964.
Piercy was the only son of Edward Piercy, of Hoxton, Middlesex, and his second wife Mary Ann Margaret (née Heaford). His father was killed in an industrial accident in 1893. Piercy was educated locally, but left school at the age of twelve to join Pharaoh Gane, timber brokers, as an office boy. He studied at night and in 1910, aged 24, he became a full-time undergraduate student at the London School of Economics. He graduated B.Sc. in 1914 and was for a time a lecturer in history and public administration at the school.
During the First World War Piercy worked for the Inland Revenue, was a member of the Allied Provisions Export Commission and a director of the Ministry of Food. For his services he was made a CBE in 1919. After the war he became trading general manager of Harrisons & Crosfield Ltd and joint managing director of Pharaoh Gane, and in the early 1930s he was one of the organisers of the first unit trusts. Between 1934 and 1942 he was a member of the . During the Second World War he rendered the government great service, notably as head of the British Petroleum Mission in Washington D.C., as principal assistant secretary in the Ministry of Supply and the Ministry of Aircraft Production and as personal assistant to the Deputy Prime Minister Clement Attlee. On 14 November 1945 he was raised to the peerage as Baron Piercy, of Burford in the County of Oxford.