Just adding a secondary offering causes this much volaitility in a stock?
Take a look at the parallels between 2008 and 2012 and you will find at least part of the answer. In July and August of 2008 there was a very large drop in stock prices due to uncertainty in the credit and debt markets. Those same issues are in evidence now. I don't think we're headed there, but people have a good memory and preparing for the worst by going to cash from high-yield (MLP-type) investments. High yield is the first to get crushed in credit market turmoil, especially because MLPs are so dependent on them to raise money. The good news is, with a few exceptions, most of the MLPs came roaring back less than a year later and have done well since.
I agree that financial equities have been taking a beating over the uncertainty of what Washington is going to do either now, or in the future with this President or a new one. It seems as if the few minutes which I get to listen to NPR financial news in the evening rush hour, recent news has been about Chase, or Morgan Stanley etc. taking a beating. I hope they are not starting to play casino gambling with other people's money and federal regulations since the 2008 fiasco have settled in. However, with MLP's you have to remember they are structured so they have to give back to their unit holders what 90-95% of their profits after CAPEX and other bills are paid. Given the choice between a good MLP and a California government bond, I would chose the MLP. IMO.