20 Pesos Bolivianos

Oxandaburu y Garvino was a commercial house operating out of Gualeguaychú, Entre Ríos province, issuing private paper currency during a period when Argentine provincial commerce ran well ahead of any coherent national monetary framework. These notes circulated locally as a substitute for hard currency that was genuinely scarce in the interior — not a banking institution in any formal sense, but a merchant firm whose credit was apparently trusted enough to float paper obligations denominated in Bolivian pesos, the unit then dominant in cross-border trade through the Río de la Plata region.

PS prefix in the Pick catalog places this squarely in private scrip territory. Survivors are rare.