I'm trying to understand the power of Berkshire float, I have a basic understanding of how it helps, if investor A has 100$ invested at 10% at the end of the year he will make 10$ (or 10%) and if investor B has 100$ and he gets 20$ from a friend who tells him "Hold this money for me for a year and I will pay you 1$ for it" he has 120$ to invest and he earned 13$ that year (12$ with a 10% return and 1$ from "underwriting profit") for a 30% advantage due to float.
But in the real world things are not so simple, in order to get float you have to have some of the 100$ invested in the operation of getting float, you have to buy a building, office chairs, computers and so on in order to generate this float and underwriting profit, so if you invest out of the original 100$ something like 30$ to generate 20$ of float you only have 90$ to invest so I was wondering if someone here can walk me through Berkshires historical numbers and how much capital is invested in the insurance businesses in order to generate how much float and how much "leverage" that float generated for Berkshire.