Billionaire Bill Ackman Has 15% of His Portfolio in This Magnificent Stock: Time to Buy?

The average investor can find compelling investment ideas by looking at what the big boys are doing. Regulations require larger asset managers to disclose their holdings every quarter, which can provide valuable insights into potential stocks to buy.One closely watched hedge fund manager is Bill Ackman, who has made a name for himself by making concentrated bets as the head of Pershing Square Capital Management. There's one business in particular that makes up a huge weighting in the fund.As of Sept. 30, Ac ...