Private equity firms, hedge funds and wealthy individuals are types of entities that might decide to act as activist investors. One well-known activist investor is Carl Icahn. He has attempted to make major changes at Yahoo!, Blockbuster, Time Warner and RJR Nabisco, among other companies. Other big-name activist investors include Kirk Kerkorian, Bill Ackman, Eddie Lampert and Nelson Peltz.
One indication that a company may have become a target for activist investors is the filing of SEC Form 13D, which must be filed when an investor purchases 5% or more of a company’s shares.