1 Austral Overprint on 1000 Pesos Argentinos

Argentina's June 1985 Austral Plan was one of the most abrupt currency conversions in Latin American history — overnight, the peso argentino was replaced at a rate of 1,000 to 1, and rather than wait for newly designed notes to come off the presses in sufficient volume, the Central Bank simply overprinted existing 1,000 peso argentino stock with the new denomination. The conversion rate was by design exactly reflected in the face value: one austral on a one-thousand peso note, no rounding required.

The Austral Plan initially succeeded in breaking triple-digit monthly inflation, but the stabilization proved short-lived. By 1989, inflation had returned with force, and the austral itself would be replaced by the convertible peso in 1992.