In the fragmented geographical, fiscal, and financial state inherited by Philip II of Spain, while the public debt reached an unprecedented level (50–60 per cent of GDP), the critical refinancing of unfunded asientos into funded juros was operated by merchant‐bankers who signed the asientos. This process is illustrated, using abundant archival documentation, by an asiento with the Maluenda brothers in 1595, which provided the Crown with steady monthly cash payments for a year with options to sell juros for two‐thirds of the credit, and a monthly rate of 1 per cent on the interim balance. Other examples are provided.