Utilize the input text as a context reference, choose the right relationship between 'Phillips 66' and 'Berkshire Hathaway' from the options.
Options: director/manager, owned by, member of, distribution format

(Reuters) - Warren Buffett's Berkshire Hathaway Inc (BRKa.N) disclosed a $4.48 billion stake in oil refiner Phillips 66 (PSX.N), rebuilding a bet it had made in the energy industry before oil prices fell.
owned by