After the bursting of the housing bubble in 2007 and 2008, the Fed began to pump trillions of dollars into the markets to keep the economy out of a depression. That money went somewhere, and for the most part, it has gone to prop up the insolvent government through the selling of Treasuries.
After 4 years, that glut of treasury buying has reached maximum velocity as yields on these bonds have fallen to their lowest levels in history.
Debt and deflation. The deathburger of a market menu.