A gold bug is a colloquial expression used to refer to people that are particularly bullish on gold. It is associated with someone who expounds the virtues of gold as an investment, and who thinks its price will perpetually increase. These people often center on the perceived threats posed to fiat currencies that make gold attractive. Gold bugs argue that because gold is priced in relation to fiat currencies, gold will, therefore, appreciate in value if fiat currencies lose their value.