Billionaires giving away their net worth to charity?

Duquesne Capital Management founder Stanley F. Druckenmiller is joining an elite group: billionaires who have stepped down from their top executive jobs to devote more time to philanthropy.

Druckenmiller, a billionaire fund manager, last year shifted $700 million to his family foundation. Before the transfer, the foundation had assets of about $6.5 million. That contribution made Druckenmiller the Chronicle of Philanthropy's top rated charitable giver in 2009.

Druckenmiller has now transferred a quarter of his reported net worth to charitable organizations and on Aug. 18 said he plans to shut down his Duquesne hedge fund to spend more time on philanthropy.

Druckenmiller joins other billionaires, including Microsoft founder Bill Gates and Citigroup Chairman Emeritus Sanford Weill, who have stepped down from top executive jobs to devote more time to philanthropy.