Although the subprime mortgage caused the financial crisis, the filmmaker decided to focus on the stock market and the various players who predicted the fall, along with folks who were able to benefit from this crisis.
While the film doesn't talk too much about finances and stocks, it tries to highlight other horrors of this world. It highlights how disconnected some of these folks become after becoming rich playing the stock market.
This film warns the viewer, especially anyone attempting to become a stock investor, to stay away from companies that aren't transparent. It tries to tell the viewer that it's better to stick with a reliable company with good fundamentals and attempt to do right by those involved.