Take context from the input text and decide on the accurate relationship between 'Berkshire Hathaway' and 'Warren Buffett' from the options provided.
Options: stock exchange, parent organization, chief executive officer, chairperson

(AP) -- 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.
chairperson