There are a large number of firms from whom correspondence survives. Whilst much of this correspondence concerns small pieces of routine business, there are a number of 'correspondent' firms whose letters can be of wider interest. The principal firms are: Finnie Brothers, Leuzinger & Co., Samuel, Phillips & Co., and Naylor Brothers of Rio de Janeiro and Buschek & Co. of Bahia. The bulk of this correspondence is for the first half of the nineteenth century: the reduction in correspondence for the latter half of the century probably reflects the changing nature of NMR's Brazilian business.

From the mid-nineteenth century onwards more of NMR's business in Brazil was with the government. The government had an account with the bank since 1825, and there is extensive documentation of a largely routine nature concerning its management. In addition to account books, the archive contains related correspondence, initially with the Brazilian legation in London and from 1840 with finance ministries in Brazil.

NMR was pre-eminent in raising capital for the Brazilian government on the London market. As early as 1825, as soon as Brazilian independence was recognised by the British government, Nathan Rothschild raised £2,000,000, and indeed was probably discretely involved in the earlier tranche of this loan which raised £1,000,000 in 1824.

NMR issued further loans in 1829 and 1852, but the majority followed the bank's appointment as exclusive financial agents in England to the Brazilian government in 1855. Between 1858 and 1914 NMR issued loans to Brazil - to the government, railway companies, and for port works and naval construction - of more than £141,000,000.

Following the 1914-1918 war NMR continued to issue loans, but frequently in partnership with Baring Brothers and J. Henry Schroder, and in conjunction with Dillon, Read in New York. Between 1921 and 1930 NMR were involved in loans to Brazil totalling £40,000,000. This period was marked by the problems of the coffee market, and the attempt and failure to control the price of coffee. NMR, although intensely sceptical of coffee valorisation, became closely involved through loans raised to finance these operations, secured on coffee.

Material in the Archive relating to loans is diverse. There are surviving examples of bonds, scrip, Treasury bills and prospectuses, and contracts, draft contracts, agreements and other legal documents. There are also accounts and registers used in the administration of the bonds following their issue and sale. Correspondence concerning the later loans is extensive, and extends to broader aspects of Brazilian public finance. Both NMR and the government had a vested interest in maintaining Brazilian creditworthiness and reputation in the capital markets, and this led to the bank's close monitoring of many aspects of Brazil's economic and financial policies. The bank was, for example, an initiator of the Montagu Financial Mission sent to Brazil in 1923 to report and make recommendations on monetary policy, and was closely involved in the rescheduling of Brazilian external debt in the 1930s.

NMR was well supplied with information concerning economic, commercial and political developments in Brazil in the interwar years by their agent in Rio de Janeiro, Henry Lynch. Lynch was formidably well connected in Brazil, and his extensive correspondence gives a vivid and robust contemporary account of these interesting years. The bank's general manager, Samuel Stephany, also visited Brazil on a number of occasions during these years.