Stocks often bounce after a 13D filing is announced. But Squire says that it is not too late to invest after the initial jump. He says that the average holding period for an activist is 15 months. Often the deals take longer to complete, and some of the biggest gains occur late in the game. Squire owns Howard Hughes ( HHC ), a stock that has benefited from a long period of activism. In 2010, veteran hedge fund operator Bill Ackman became chairman of the company, which operates commercial developments, including a Las Vegas project that was owned by the estate of billionaire industrialist Howard Hughes. Ackman is known for a series of high-profile activist moves, including investments in Target ( TGT ) and Procter & Gamble ( PG ). As chairman of Howard Hughes, Ackman has faced a series of problems. Some of the real estate projects stumbled during the financial crisis, and development efforts were forced to halt. Now Ackman is obtaining financing and pushing forward with projects.