100 Pesos

Banco de Londres y Sud America was the Argentine branch of the London and River Plate Bank, one of the major British merchant banking interests operating in the Río de la Plata region from the 1860s onward. Provincial and foreign-chartered banks in Argentina were permitted to issue their own notes during this period, creating a fragmented currency environment that persisted until the Banco Nacional took firmer control of emission in the early 1880s. The undated "18__" format indicates blanks completed at the branch upon issue — common practice for ABNC-printed provincial stock held in reserve against demand.

The American Bank Note Company held long-standing contracts with numerous South American banking clients through this period, and plates were often retained and reused across successive authorization runs. Worth confirming whether this example shares plate geometry with related S-series issues from the same bank.