100 Dollars - Elizabeth II 4th Portrait - Koala - Platinum - The Arts

Australia's platinum koala series, launched in 1988, was among the first government-issued platinum bullion programs in the world — competing directly with the Soviet Palladium Ballerina and the Isle of Man Noble for collector attention in a market that was still deciding whether platinum belonged alongside gold and silver as an investment-grade metal. The 2003 "Arts" release is one of the themed annual variants Perth introduced to differentiate proof issues from the standard bullion strikes, a strategy that kept the series commercially viable well into the 2000s.

The pad printing notation in the composition field indicates applied color, a technique Perth adopted cautiously and only on select proof issues.