Alan Greenspan (born March 6, 1926) is an American economist who served as the 13th chairman of the Federal Reserve from 1987 to 2006. He works as a private adviser and provides consulting for firms through his company, Greenspan Associates LLC.

First nominated to the Federal Reserve by President Ronald Reagan in August 1987, he was reappointed at successive four-year intervals until retiring on January 31, 2006, after the second-longest tenure in the position, behind only William McChesney Martin. President George W. Bush appointed Ben Bernanke as his successor. Greenspan came to the Federal Reserve Board from a consulting career. Although he was subdued in his public appearances, favorable media coverage raised his profile to a point that several observers likened him to a "rock star". Democratic leaders of Congress criticized him for politicizing his office because of his support for Social Security privatization and tax cuts.

Many have argued that the "easy-money" policies of the Fed during Greenspan's tenure, including the practice known as the "Greenspan put", were a leading cause of the dot-com bubble and subprime mortgage crisis (the latter occurring within a year of his leaving the Fed), which, said The Wall Street Journal, "tarnished his reputation". Yale economist Robert Shiller argues that "once stocks fell, real estate became the primary outlet for the speculative frenzy that the stock market had unleashed". Greenspan argues that the housing bubble was not a result of low-interest short-term rates but rather a worldwide phenomenon caused by the progressive decline in long-term interest rates - a direct consequence of the relationship between high savings rates in the developing world and its inverse in the developed world.