About half of the investors in T. Boone Pickens's energy-oriented equity hedge fund have asked to withdraw their money on the heels of losses of about 60% this year, according to people close to the matter. Mr. Pickens and his investment firm have lost $2 billion since peaking in late June, Mr. Pickens said Sunday on the CBS program "60 Minutes."

His fund, BP Capital, will have about between $400 million and $500 million after expected withdrawals. It started the year with about $2 billion. A few weeks ago, Mr. Pickens moved...