A ‘Giffen good’ is a strangeness. When its price increases, its demand does not fall, it rises. Simply because it is an essential good – not substitutable – which constitutes a significant part of the buyer’s income.
In times of economic stress, companies that produce Giffen goods are a safe-haven for the stock market investor.
We are now in a time of economic stress; here is an example of the Giffen portfolio, with seven good old essential stocks!