Berkshire Hathaway Inc. New (BRK.B) is a diversified holding company. Insurance is its core business and is conducted mainly through GEICO, Berkshire Hathaway Reinsurance Group, and Berkshire Hathaway Primary Group. Berkshire also owns BNSF Railway, Berkshire Hathaway Energy, and manufacturing, service, and retail businesses including Precision Castparts, Lubrizol, Clayton Homes, Marmon, and IMC/ISCAR. The group uses a highly decentralized management structure and generated about $371.4 billion in operating revenue in 2025.