The following commentary comes from an independent investor or market observer as part of TheStreet's guest contributor program, which is separate from the company's news coverage.By James Brumley NEW YORK ( StreetAuthority) -- It's that time of year again, when investment managers are required to disclose their fund's holdings to the SEC, and by extension, to all investors. And for most investment companies and hedge funds, it's a pretty straight-forward process . . . just make a list of all the stocks you own, and how much of them you own. If you're Greenlight Capital's David Einhorn, however, it's not quite that simple. With Einhorn's willingness to hold short as well as long positions (not to mention his willingness to speak out about them) in the $7 billion hedge fund, it's a bit of a process to truly figure out what he's thinking, or trading. On the other hand, considering his fund has returned an average of 21% per year for the past 15 years, sifting through the data is worth the effort.