The South American Funds National Exchequer was established in 1818 to contribute to the consolidation of the public debt of Buenos Aires. It was the first financial innovation since the revolutionary outbreak in Buenos Aires, and its failure allowed the authorities to understand the limits of the fiscal and financial commitment they proposed by means of that institution. Its suppression, in 1821, offered an antecedent to develop a deep reform of the financial institutional matrix of Buenos Aires, based on the Public Credit office, the Amortization Exchequer and the Bank of Buenos Aires. The South American Funds National Exchequer was, thus, the first movement in the negotiation on the terms of the financial commitment assumed by the nascent State. This paper analyzes the 973 accounting entries of the institution, providing an interpretation of that failure and its importance for the course of public finances in Buenos Aires.