4 Your best friend has done you a massive favour recently, and is now asking you if you’d like to invest in Peruvian shrimp farming.

This, your chum says, is a sure winner. The demand for shrimps is increasing all over the world, especially in restaurants and in supermarkets with middle-class clientele, and above all in China where the population is growing. Your friend is putting all their life savings into this scheme. You know nothing about shrimp farming and nothing about Peru. If you invest which classic rule of good investment decision making will you be breaking?