Joel Greenblatt recently wrote an investment book titled "The Little Book That Beats The Market." It included a description of an investment strategy focusing on a magic formula with two inputs – high return on capital and a high earnings yield. The book is a great intro into factor based equity screening. Currently he owns four stocks – Wal Mart (WMT), American Express (AXP), Autozone (AZO), and Aeropostale (ARO). You can follow along with his holdings here.
Interestingly enough, Grennblatt’s siter runs her own hedge fund (Saddle Rock Capital) with ~ $170M AUM. Even more interesting, she only owns two stocks – Aeropostale(ARO, 2.9M shares) and Abercrombie and Fitch (ANF, 1.2M shares). Talk about some serious cajones! But then again, it was none other than Buffett himself that said, "Wide diversification is only required when investors do not understand what they are doing."