Berkshire Hathaway owns businesses in insurance, railroads, energy, manufacturing and retail, and invests in publicly traded companies. BRK-B represents its Class B shares.
History and development
Berkshire Hathaway was formed through a textile-company merger in 1955. Warren Buffett took control in 1965, and entry into insurance in 1967 helped transform it from a textile business into a diversified owner of operating companies and securities.
References: Berkshire Hathaway: fifty-year review