The earliest record of the business enterprises of the Rathbones of Liverpool is the 1742 MS daybook of William Rathbone II, documenting a timber and ship-owning business.
"My grandfather's [William Rathbone IV] house sold the first American cotton grown in the United States, that ever was imported to this country... it came in eight bales and three barrels, and was seized at the Custom House for breaking the navigation laws, which stipulated that produce must come from any country in vessels belonging either to that country or to England, and they held that cotton was not grown in America. It was I believe, eighteen months before it was sold, as the staple was of different length to any in use then. I was told that my grandmother Rebecca had for a long time a sample of this cotton, and my grandmother Greg a sample of the cloth made from some of it; but neither has been found in our day." - William Rathbone, 'A sketch of Family History during four generations' 1894, p.9.
William Rathbone III joined and continued his father's trade, by mid century had succeeded in establishing an international merchanting and commission business. The firm began to extend the range of commodities in which they traded: timber, salt, iron bars, linen, leather, tobacco, tallow, wheat, rye and rice and earthenware, and trading links were established with the West Indies, North Europe and America. The Rathbones were amongst the first firms to import American cotton to Britain: a commodity that was to become increasingly important to their business. William Rathbone III was also responsible for leasing the firm's new premises at Cornhill, in Liverpool's dock area, where they conducted business until 1838.
William Rathbone IV took over the firm on his father's death in 1789; by this time the business was being conducted in staunch opposition to Liverpool's involvement in the slave trade and was becoming a shipping agency specialising in the American trade. In 1790 William Rathbone IV's brother-in-law, Robert Benson, joined him in partnership as Rathbone and Benson. James Cropper joined the partnership in 1795, but it was dissolved within a year due to Benson's ill health. A new partnership (Rathbone, Hughes and Duncan) was formed between William Rathbone IV, William McMurdo Duncan and William Hughes in September 1796, which continued the trade as commission merchants.
On the death of William Rathbone IV in 1809, his sons William V and Richard, advised to set up their own business as commission merchants, formed the partnership of William and Richard Rathbone; their main business was cotton commission work. In 1814, Adam Hodgson joined the partnership (now Rathbone Hodgson and Co.); on his retirement in 1824, James Powell became the new partner in the business now trading as Rathbone Bros. and Co.
In 1842 William Rathbone VI joined his father as partner in the firm, followed in 1847 by his brother Samuel Greg Rathbone. Over the next three decades the company enjoyed a period of marked expansion. The Rathbones trade with America, importing cotton and grains and exporting China tea and Brazilian coffee, was strengthening, and another partner, Henry Wainwright Gair, established an agency in New York to promote this business further. In 1857, Gair was succeeded by William Lidderdale, followed by J.R. Busk and in 1867 it became a commission house under the name of Busk and Jevons.
In the 1840s Samuel Greg Rathbone had visited China on behalf of the firm and subsequently established two Chinese branch houses, in Shanghai and Canton, which operated under the name of Rathbone, Worthington and Co. to purchase teas and silks in China, and to export British-made products to China. The Chinese branch houses were closed in the early 1850s, but trade with China continued successfully, with Rathbone Bros. becoming one of the largest tea importers in Britain. A London house was opened under the direction of William Lidderdale, later joined by William Gair Rathbone VII. The house expanded to handle trade in a variety of commoditites, including silk, rice, sugar, and coffee, until financial problems forced its closure in 1898. Other trade links were forged with Egypt, where Rathbone Bros. handled wheat, corn and cotton consigned to them by Tod, Rathbone and Co. in Alexandria, and with South America in the coffee trade with Rio, and, through association with John D. Jackson, Uruguay, in the import of the first salted beef to Britain. Rathbone Bros maintained trading interests with India; 1841 they became the Liverpool agents for the East India Company, dealing in cotton and textiles.
Towards the end of the nineteenth century, faced with intense competition and the effects on merchanting of improved communications by steam power and telegraphs, Rathbone Bros was facing a critical loss of profits. The business finally underwent restructuring in 1912, shifting its emphasis from merchanting to the provision of financial services; in 1988 the firm merged with Comprehensive Financial Services Ltd to form Rathbone Brothers Plc.