Greenspan Put

The Greenspan put refers to the market expectation, prevalent during Alan Greenspan's tenure as Chairman of the Federal Reserve (1987–2006), that the central bank would intervene to support asset prices and liquidity during financial stress. The term is a financial analogy to a put option: investors believed they were protected against severe downside risk because the Fed would cut rates and inject liquidity whenever markets threatened to collapse. This expectation systematically encouraged risk-taking by socializing losses while privatizing gains.

The Greenspan put was not an explicit policy but an emergent property of observed behavior. After the 1987 stock market crash, the 1998 Long-Term Capital Management crisis, and the 2001 dot-com bust, the Fed consistently responded with aggressive rate cuts. Market participants learned the pattern and priced it into their strategies. The result was a moral hazard dynamic in which the very presence of a perceived backstop inflated asset bubbles and concentrated systemic risk. The put expired in 2008, when the Fed's interventions proved insufficient to prevent global financial collapse — demonstrating that implicit guarantees are credible only until they are tested.