The article explores three of the general trading companies founded by Marquis of Pombal – the Companhia Geral do Grão-Pará e Maranhão (Grão-Pará and Maranhão General Trading Company, 1755), the Companhia Geral da Agricultura das Vinhas do Alto Douro (Agriculture of Alto Douro Vineyards General Trading Company, 1756) and Companhia Geral de Pernambuco e Paraíba (Pernambuco and Paraíba General Trading Company, 1759) –, both in terms of accounting and corporate governance rules. In order to identify the similarities and differences between the founding documents of the three companies, this text adopts a qualitative research approach that uses primary and secondary research sources. This paper represents a contribution to a better understanding of 18th Portuguese accounting and a contribution to expand the knowledge of the governance model of 18th century Portuguese companies, providing, in this way, a systematization of the factors that contributed to the foundation of the three companies combined with the analysis of its internal functioning within the framework of its corporate governance rules. The article explores three of the general trading companies founded by Marquis of Pombal – the Companhia Geral do Grão-Pará e Maranhão (Grão-Pará and Maranhão General Trading Company, 1755), the Companhia Geral da Agricultura das Vinhas do Alto Douro (Agriculture of Alto DouroVineyards General Trading Company, 1756) and Companhia Geral de Pernambuco e Paraíba (Pernambuco and Paraíba General Trading Company, 1759) –, both in terms of accounting and corporate governance rules. In order to identify the similarities and differences between the founding documents of the three companies, this text adopts a qualitative research approach that uses primary and secondary research sources. This paper represents a contribution to a better understanding of 18th Portuguese accounting and a contribution to expand the knowledge of the governance model of 18th century Portuguese companies, providing, in this way, a systematization of the factors that contributed to the foundation of the three companies combined with the analysis of its internal functioning within the framework of its corporate governance rules.