Justice in this case might look simple -- take a bunch of money from the companies and give it to the employees that would have earned it (and penalties, of course). The problem is, this affects a bunch of innocent bystanders. These are top stocks in this country. Lots of retirement funds are wrapped up in these stocks. If you penalize the companies the "rightful" amount, you will definitely harm their stocks, which means members of the police retirement fund in Maine (across the country) stand to lose their asses through no fault of their own.
It's easy to throw around ideas of vengeance & justice on these kinds of situations, but the world is a complicated place, and sometimes what appears obvious and "common sense" is actually the most harmful thing you can do.