About a month and a half into each new quarter, every institutional fund that manages more than $100 million in qualifying assets is required to file a Form 13F with the Securities and Exchange Commission (SEC). The 13F documents all the investments the fund holds at the end of the prior quarter. Looking at these filings can be quite interesting for retail investors, as they show what Wall Street's high-profile investors have been up to recently.Billionaire investor Bill Ackman founded hedge fund Pershing S ...