BBRK.ABerkshire Hathaway Inc.

BRK.A is Berkshire Hathaway's original share class: the same holding company as BRK.B, but the stock has never been split and costs as much as a small flat.

The difference between classes is not the business but denomination and rights. Class A has never been split as a matter of principle: a high price discourages speculative trading and attracts holders who keep the stock for years. Class B was issued later as a fraction of class A to make entry affordable, and can be obtained by converting from A but not the reverse.

Class A carries substantially more votes per dollar invested, so it is chosen by those who care about the annual meeting. Economically both shares give the same stake in the same set of assets, and the holding company pays no dividend on either as a matter of principle.

The business is built around insurance: premiums are collected today and claims paid later, and the gap between them funds acquisitions. Alongside sit wholly owned businesses — railroad, energy, industry — and a portfolio of listed equities whose revaluation makes quarterly profit a figure that says little about how the business is doing.