Isn't it obvious why he's selling shares? He's a man of country and pride - and smells malice/greed at this bank well beyond his tolerance. He could have moved his billions long ago to more profitable investments, but the humanity of this particular bank was always a bit stronger than the other big players.
If you bet on malice and greed, you're betting a short term bet. Bank of layoffs, it lost its humanity and "America"