Berkshire Hathaway is the investment company led by Warren Buffett and regularly ranks among the world's largest companies by market capitalization.
Berkshire Hathaway began as a textile manufacturer, but Warren Buffett and Charlie Munger transformed it into a diversified holding company. Its businesses and investments have included insurance, railroads, utilities, energy, manufacturing, retail, and large stakes in publicly traded corporations.
Insurance is central to Berkshire's structure. Premiums collected by its insurance subsidiaries create “float,” money that can be invested until claims must be paid. This model helped the company build capital while its operating businesses supplied additional earnings.
Berkshire is unusual among mega-cap companies because it traditionally did not pay a regular dividend and is known for its annual shareholder meeting in Omaha, Nebraska. Its market capitalization reflects the value investors assign to the entire holding company, not merely to its public-stock portfolio.