The difference between first & second level thinking (by Howard Marks)

Moats

Sustainable Competitive Advantage or as Buffet calls them "Moats". Moats can come from a combination of:

1. Supply side economies of scale
2. Demand side economies of scale (network effects)
3. Brand
4. Regulation
5. Intellectual property

The evidence that a moat exists is pricing power. If pricing power is dropping the moat is shrinking. 

BillG -"Intellectual property has the shelf life of a banana".

If the source of the pricing power is hard to identify, the source is usually brand.