He took his schooling at York, and, as a young man, held posts as a clerk in that city He early showed his literary taste and talent by publishing a Guide to the City, by frequent correspondence with the "Sheffield Iris," and by the delivery of lectures. Having served as a clerk under a stamp distributor, he passed to the Yorkshire Fire and Life Office at York, then to the banking house of Messrs. Leatham, Few, and Co., at Wakefield (1843–1846). (Proceedings of the Royal Society of London)
He then moved to London and worked for three financial institutions:
- the Agra Bank (1846–1851)
- secretary to the Globe Insurance Company (1851–1862)
- chief officer in the banking-house of Glyn, Mills & Co. (1862–1881)
Notwithstanding the continuous pressure of an active business life he found time to contribute many valuable articles to the magazines and newspapers, and took an active part in the proceedings of the Royal Statistical Society (of which he was one of the honorary secretaries, editor of its journal, and in President (1869–1871)) and the Political Economy Club. He was also elected a fellow of the Royal Society.
His extensive knowledge of banking was displayed in the evidence which he gave before the select committee on the Bank Acts in 1857. He collaborated with Thomas Tooke in the two final volumes of his History of Prices and was responsible for the greater part of the work in those volumes. For nineteen years he wrote a survey of the commercial history of the year in The Economist. He died at Torquay on 23 March 1882 and was buried at West Norwood Cemetery.
After his death his friends founded, in perpetuation of his memory, a Newmarch Lectureship in economic science and statistics at University College, London. Arthur Bowley, Josiah Stamp, and Udny Yule were amongst the distinguished Newmarch lecturers.
- "The Death of Mr. William Newmarch" Journal of the Statistical Society of London, Vol. 45, No. 1. (Mar., 1882), pp. 115–121.
- Obituary Notices of Fellows Deceased, Proceedings of the Royal Society of London, Vol. 34. (1882–1883), pp. xvii–xix.
There is a section on Newmarch in
- Paul J. FitzPatrick "Leading British Statisticians of the Nineteenth Century," Journal of the American Statistical Association, Vol. 55, No. 289. (Mar., 1960), pp. 38–70. Reprinted in Studies in the History of Statistics and Probability II Edited by M G Kendall and R L Plackett, London 1977.
There is more information about Newmarch in the following AIM25 library record
Newmarch is placed among the classical economists in the opening (and sample) chapter of the following