Utilize the input text as a context reference, choose the right relationship between 'Berkshire Hathaway' and 'Insurance' from the options.
Options: brand, headquarters location, owned by, industry

Insurance Australia Group has formed a strategic relationship with Warren Buffett's investment giant Berkshire Hathaway that will see the US group take a 3.7 per cent stake in IAG via a $500 million placement.
industry