For all the contributions of the nearly 70 businesses Berkshire owns, it is essentially an insurance company. The unit produced $3.3 billion (down from $3.8 in 2006) of the company's $13 billion in earnings in 2007. Further, $37 billion of the company's reported $44 billion in cash and cash equivalents belong to insurance, proving to be another stellar run for the company.
According to Buffett: Finally, our insurance business – the cornerstone of Berkshire – had an excellent year. Part of the reason is that we have the best collection of insurance managers in the business – more about them later. But we also were very lucky in 2007, the second year in a row free of major insured catastrophes.