Warren Buffett Boosts Largest Energy Position Phillips 66 by admin | Jan 8, 2016 | Uncategorized | 0 comments Warren Buffett (Trades, Portfolio)’s Berkshire Hathaway (NYSE:BRK.A)(NYSE:BRK.B) empire purchased a relatively small amount of shares of their largest energy position Phillips 66 (NYSE:PSX) as its share price declined this week.