BRK.BBerkshire Hathaway Inc.

Berkshire Hathaway is a holding company where insurance supplies the money to invest, and the investments and wholly owned businesses supply the profit.

The structure is built around insurance: GEICO and the reinsurance units collect premiums today and pay claims later. The gap between those moments is the float — money the holding company controls until claims fall due. Historically it financed the acquisitions and the equity portfolio.

The second part is wholly owned businesses: the BNSF railroad, energy assets, industrial and retail operations. They produce operating profit independent of market quotations. The third is a portfolio of listed equities highly concentrated in a few positions; its revaluation runs through the income statement and makes quarterly profit an extremely volatile figure that says little about how the business is doing.

Two features stand out: the holding company pays no dividend as a matter of principle, preferring to reinvest, and it has accumulated a very large cash position whose size has itself become a topic of debate. Class B differs from class A only in denomination and voting rights, which makes it accessible to retail investors.