Net Net: Promoting innovation and managing change
Net Net: Promoting innovation and managing change

Welcome to the golden age of activist investors

Carl Icahn
Scott Eelis | Bloomberg | Getty Images

Carl Icahn moves stocks with tweets now.

Yesterday . The stock immediately was bid upward.

This much is clear: we're living in the golden age of activist investors.

Almost every day there's a new story that runs like this: hedge fund manager "X" has purchased a stake in an iconic American company that he thinks will be worth more—if only the company will follow his plan. It's now a familiar part of the Wall Street landscape.

The names are familiar to anyone reading the financial headlines: David Einhorn of Greenlight Capital. Nelson Peltz of Trian Partners. Dan Loeb of Third Point. Paul Singer of Elliot Management. Bill Ackman of Pershing Square.

It wasn't always like this, of course.

Just 10 years ago, activist hedge funds had less than $12 billion under management. Today that number tops $65.5 billion, according to the Wall Street Journal. Much of this growth has come from investments by large institutional investors, including pension funds and university endowments. Activism has gone mainstream.