Always thought it was a waste of time but been looking on eBay and realise people pay big money for some old notes in urcirculated condition.. Superannuation Investments There is an interest in the investment of rare banknotes through superannuation funds, as a means of diversifying funds. Rare Banknotes – The Best Producing Asset in Australia from 1990-2000. Rare banknotes as both a superannuation and private investment have given outstanding returns over 30 years of survey’s conducted from 1977 up to 2000. Annual capital returns of 15-20% in the superior graded banknotes of Uncirculated. Annual capital growth from Australian Banknote and Coin Catalogues have shown from 2010 to 2011 an average growth of approximately 10-15% per annum.