(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.
Analyze the relationship between 'Phillips 66' and 'Berkshire Hathaway' within the context of the input sentence.
Options: member of, distribution format, owned by, director/manager