This paper studies the "confidential holdings" of institutional investors, especially hedge funds, where the quarter-end equity holdings are disclosed with a delay through amendments to the Form 13F and are usually excluded from the standard databases. Evidence supports private information as...

This paper formally analyzes the biases related to self-reporting in hedge fund databases by matching the quarterly equity holdings of a complete list of 13F-filing hedge fund companies to the union of five major commercial databases of self-reporting hedge funds between 1980 and 2008. We find...