Pershing Square Capital Management

Icahn Buys Big Stake in Herbalife, Heats Up Feud With Ackman

A clash between Wall Street titans is flaring again Friday after Carl Icahn grabbed a 13 percent stake in Herbalife, a supplement company that Pershing Square Capital Management's William Ackman shorted heavily and publicly, calling it a massive pyramid scheme.

Activist Investor William Ackman Targets Procter & Gamble's CEO

William Ackman's Pershing Square Capital Management has taken a $2 billion position in Procter & Gamble, and it's almost certain he wants to oust the CEO. This is hardly Ackman's first attempt to buy big into a company and shake things up -- but it is his biggest.

For Investors, Lessons from the Death of Borders

Following Chapter 11 bankruptcy, Borders now has to liquidate its remaining stores. But there's a bright side to the big box bookseller's death: Its long and tragic tale provides plenty of fodder for investors. Use these lessons to ensure that your future investments have a happier ending.