Utilize the input text as a context reference, choose the right relationship between Berkshire Hathaway and Warren Buffett from the options. Options: product/material produced, manufacturer, distributed by, industry, position held, original broadcaster, owned by, founded by, distribution format, headquarters location, stock exchange, currency, parent organization, chief executive officer, director/manager, owner of, operator, member of, employer, chairperson, platform, subsidiary, legal form, publisher, developer, brand, business division, location of formation, creator.

— Warren Buffett is making the biggest bet of his long investment career, a $32.36 billion buyout of Precision Castparts in a deal that will continue to reshape his Berkshire Hathaway conglomerate.

Answer: director_/_manager