Stanley Freeman Druckenmiller is an American billionaire investor, philanthropist, and former hedge fund manager. He is the founder, former chairman, and president of Duquesne Capital, which he established in 1981. He closed the fund in August 2010, at which point it managed over $12 billion in assets. From 1988 to 2000, Druckenmiller managed money for George Soros as the lead portfolio manager for Quantum Fund.