Alan Greenspan served as Chairman of the Federal Reserve from 1987 to 2006, making him the second longest serving Fed chair. He supported free market policies and opposed government intervention in the economy. However, his reputation declined as the housing and stock market bubbles he failed to regulate burst after he left office. Greenspan later acknowledged flaws in his ideological opposition to derivatives regulation. As Fed Chair, he was a major proponent of monetarism and believed that controlling the money supply was key to managing the economy.