Soros, George

A Hungarian-American billionaire investor and philanthropist best known for "breaking the Bank of England" on Black Wednesday (September 16, 1992), when his Quantum Fund made approximately $1 billion by shorting the British pound as it was forced out of the European Exchange Rate Mechanism. Soros's theory of reflexivity -- the idea that market participants' biases can create self-reinforcing feedback loops that drive prices away from equilibrium -- has influenced a generation of macro traders and remains one of the most important contributions to market philosophy.