Since stockbrokers lived on commissions generated by deals, it was essential that they maintain a certain turnover. This, once again, is where the dear old private client came in useful. The cynical term "churnover" was coined by stockbrokers to describe a simple act of survival. When markets go horribly quiet, as they do from time to time, there is a very real risk that securities traders may face the possibility of a diminished income due to the thin trade in shares.

That level of candour has given Buffett the reputation of a maverick on Wall Street. While the Street respects his achievements, his pronouncements about not worrying if Berkshire and the stocks it owns stopped trading for long stretches are anathema to an industry that survives on turnover, if not 'churnover.'

What does an investor get for a lot of furious trading? Sometimes, good performance. Sometimes, bad performance. Always, trading costs.