Describing a perceived attempt of former Federal Reserve Chair Alan Greenspan to prop up the securities markets by reducing interest rates and helping money flow into the markets. Coined in the late 1990s, investors presume they could liquidate their stocks at a fixed price or prior to a certain date as if there was a built-in put option. They believed Greenspan would maneuver monetary policy and continue to keep market stability. While it affected the markets, this was not likely his objective.