With a reputation for secrecy and a penchant for confidentiality, the hedge fund industry hasn’t yielded a bumper crop of empirical data for researchers to feast on. One of the few square meals academics have been able to find is the ubiquitous 13F filing. Regular readers of this website are familiar with our rich vein of hedge fund data. Although these quarterly SEC filings cover only large long equity positions held by hedge funds (and all other institutional investors), they provide a rare insight into the skill of hedge fund managers. This study, for example, uses 13F’s to judge whether hedge fund managers mis-mark their equity positions. This one concludes that despite what you might expect, investors do not mimic Warren Buffett’s 13F filings. Another tries to do a sanity-check on hedge fund databases. And this guest contributor uses 13F filings to mimic the holdings of hedge fund managers.