Between 1800 and 1820, Buenos Aires and the former colonial Viceroyalty of Rio de la Plata faced an unprecedented fiscal crisis caused by the revolutionary wars, eventually solved by levying forced loans. This paper considers the unintended institutional consequences of these loans. The novel devices allowed (1) the holders of forced-loan coupons to use these bonds to pay off debts incurred in customs duties and (2) the holders of bills of exchange involved in the provisioning of the military to use these bills to pay part of their forced loans. Starting with the conceptualisation of the institutional order as a complex system, this paper examines the interactions among the circulation of financial paper bills, the financing of war and changes in the position of the merchants' guild and the legal framework for Atlantic trade. It thereby contributes to renewing institutional change approaches in the Spanish-American context.