 Buying shares of Bank of America NYSE: BAC is a habit Warren Buffett just cant seem to shake. According to a regulatory filing submitted late Tuesday, the renowned investors Berkshire Hathaway NYSE: BRK.ANYSE: BRK.B has spent 2.07 billion since the middle of last month on Bank of America common stock in a series of purchases. This gives Berkshire a stake of 11.9 in the big lender, making it the largest publicly traded company in its portfolio in terms of total number of shares. 