The Federal Reserve (the Fed), the central bank of the United States, prints money and buys the national debt (treasuries) in order to increase bank reserves and stimulate the economy. The Fed is doing this to such an extent that they are now monetizing (printing and buying national debt) 70% of all the debt issued since October, roughly when they started . They refuse to call it quantitative easing (QE) (despite it meeting the literal definition of QE). It's why markets are going up despite zero increase in overall corporate profits and mediocre economic growth. Endless artificial stimulus like this, is why the economy shuffles from bubble to bust.