What is the relationship between 'Warren Buffett' and 'Berkshire Hathaway' in the context of the input sentence.
Options: owner of, product/material produced, developer, platform

With the $37.2 billion deal to buy Precision Castparts (NYSE: PCP - news ) announced Monday, US investment guru Warren Buffett is extending his storied Berkshire Hathaway (Sao Paolo: BERK34.SA - news ) holding company.
owner of