Which company is famous for holding a portfolio of businesses under Warren Buffett's leadership?

Berkshire Hathaway is the company famous for holding a broad portfolio of businesses under Warren Buffett's leadership.

Berkshire Hathaway is a holding company with wholly owned operations and major investments in publicly traded companies. Its businesses have included insurance, railroads, utilities, energy, manufacturing, retail, and services. Buffett became chairman and chief executive after acquiring control of the struggling textile company in the 1960s and transformed it into a diversified investment group.

Insurance is central to Berkshire's structure because premiums provide investment capital known as float. Berkshire's most famous insurance businesses include GEICO and reinsurance operations, while BNSF Railway is one of its major non-insurance subsidiaries.

Berkshire Hathaway is not a mutual fund and does not simply track an index. It owns operating companies and makes concentrated investments, which makes its structure different from BlackRock's asset-management business.