For example, two notable value investors operate businesses that fall into this category -- Tom Gayner at Markel and Warren Buffett at Berkshire Hathaway ( NYSE:BRK-A ) ( NYSE:BRK-B ) .
What is the relationship between 'Warren Buffett' and 'Berkshire Hathaway' in the context of the input sentence.
Options: industry, owned by, owner of, stock exchange