For decades, Berkshire Hathaway (NYSE:BRK.B) Chairman and CEO Warren Buffett adopted a conservative investment approach, favoring retail and banking stocks while giving a wide berth to more volatile sectors such as energy and tech. Indeed, big American banks have been Warren Buffett's favorite investment for decades as he considers them a vital part of the American infrastructure, a nation he continually bets on. However, Berkshire Hathaway has always operated on Buffett’s famous mantra of buying when the market…
