100 Dollars - Elizabeth II 4th Portrait - Kangaroo - Gold Bullion Coin

Perth Mint's four-nines gold bullion program dates to 1986, when Australia displaced South Africa as the preferred source for investment-grade gold coins among institutional buyers — largely because the Rand's .9167 fineness was increasingly seen as a liability in a market demanding purity benchmarks. By 2005, the one-ounce kangaroo had become one of the few bullion issues worldwide to change its reverse design annually, a deliberate policy to discourage melting and stimulate collector crossover demand.

KM#689 corresponds to the specific 2005 reverse type, making die attribution straightforward for this date.