To see the list of the most profitable industries in the last 12 months, go to Sageworks. Here is the list. Notice that some of them are medical or legal. Those industries have a very important barrier to entry, a license. This is something that comes up in my micro class and my ECON 1301 class. Insurance is there and in many states there are lots of costly regulations that act as a barrier. Mining might involve either big start up costs or control over a natural resource. Barriers to entry keep out new competitors, allowing the existing firms to keep their above average profit rates.