(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.
Take context from the input text and decide on the accurate relationship between 'Phillips 66' and 'Berkshire Hathaway' from the options provided.
Options: director/manager, owned by, member of, distribution format