So I just realised that Bill Gross also collects stamps it seems that he spends quite a bit on stamps actually. Between $50 to $100 million of his fortune has been spent on his stamp collection. Just recently, he sold off a portion of his stamp collection for charity purposes.
In fact, I read that he has also collected lots of price data on transacted stamp prices. It looks like one of the best investors in the world also agrees that stamp collecting can also form a significant part of one's investment portfolio!
Stamps truly provide an alternative investment for the wealthy. It provides a good form of diversification and has little correlation with the overall stock market. Time to invest in some stamps?