A description of the perceived attempt of then-chairman of the Federal Reserve Board, Alan Greenspan, of propping up the securities markets by lowering interest rates and thereby helping money flow into the markets.

Investors assumed that they would be able to liquidate their stocks at a set price at or before a future date as if there was a built-in put option. They believed that Greenspan would manipulate monetary policy and continue to maintain market stability. While the former Fed chair's actions did have an effect on the markets, it was not necessarily his objective.
The term was coined in 1998 after the Fed lowered interest rates following the collapse of the investment firm Long-Term Capital Management. The effect of this rate reduction was that investors borrowed funds more cheaply to invest in the securities market, thereby averting a potential downswing in the markets.

On February 1, 2006, Ben Bernanke replaced Alan Greenspan as the Federal Reserve Board chairman.