Activist investors take a hands-on approach to investing. They buy massive positions in companies, then grab board seats and force corporate ballots to change them from the inside. Their goals are simple: They just want to wring the most value out of portfolio firms that are misusing their assets.
While being an activist investor can be lucrative, it isn't easy. After all, it requires buying big, hulking positions in a small handful of stocks.
But that's exactly why it can be so worthwhile to peek into the portfolio of Ackman's firm, Pershing Square Capital Management. Today, we're taking a look at five of the firm's favorite stocks for 2012.>>5 Stocks With Big Insider Buying To do that, we're digging into his firm's 13F. Institutional investors with more than $100 million in assets are required to file a 13F -- a form that breaks down their stock positions for public consumption. From hedge funds to mutual funds to insurance companies, any professional investors who manage more than that $100 million watermark are required to file a 13F. And with more than $8 billion in equity alone under management, Pershing Square certainly fits that description. Without further ado, here's a look at five of his favorite stocks.