This article examines the financial strategies employed by Genoese businessmen in Atlantic Castile during the late fifteenth and early sixteenth centuries, focusing on the relative value of private enterprises. It reveals how the interplay between Castilian market characteristics and the unique financial culture of Genoese merchants predominantly supported short-term and transient economic ventures. These methods significantly reduced the need for centralised corporate structures and redundant accounting procedures, supported by a robust notarial system. Consequently, trading in securities and credit extensions became prominent features of this financial market. The research demonstrates that the widespread use of account money, credit and bills of exchange allowed Ligurians to engage in trade and access markets with flexibility and agility through quantitative and functional economic analyses. It also highlights the importance of various credit arrangements, such as loans, bills of trade, or IOUs, which extend beyond merely deferring payments.