Vultures circling: Activists love these stocks

Bill Ackman
Adam Jeffery | CNBC

Shares of Mondelez surged Thursday after Bill Ackman took a giant stake in the Oreo maker.

The Pershing Square honcho joins his activist peers, Nelson Peltz of Trian and Ralph Whitworth of Relational Investors, in the stock

This isn't the first time numerous of the most well-known activists have teamed up on a stock. There are at least six other U.S. companies with multiple barbarians at their gates and most of these stocks trouncing the market this year because of their involvement.

Studies show that when an activist gets involved in a stock, the shares tend to outperform the market over the short term and long term. So what about when there are two or three?