The Greenspan put was a monetary policy response to financial crises that Alan Greenspan, former chair of the Federal Reserve, exercised beginning with the crash of 1987. Successful in addressing various crises, it became controversial as it led to periods of extreme speculation led by Wall Street investment banks overusing the put's repurchase agreements (or indirect quantitative easing) and creating successive asset price bubbles. The banks so overused Greenspan's tools that their compromised solvency in the global financial crisis of 2007–2008 required Fed chair Ben Bernanke to use direct quantitative easing (the Bernanke put). The term Yellen put was used to refer to Fed chair Janet Yellen's policy of perpetual monetary looseness (i.e. low interest rates and continual quantitative easi