About that tax hike...

Maybe I'm not seeing clear this am, but people like Sergey Brin, Walter Buffet, and others cited in this article seem to be making money through their shares of stock. Remember, stock is not taxed until it is sold. So, it is probably safe to say that the most that they will pay would be the AMT -- which is vastly reduced by charitable contributions. How does increasing the tax rate on earned income change this for these 1 percent??