In 2008, to stave off the worst financial crisis since the Great Depression, the Fed began a program of “quantitative easing” to save the economy, eventually buying trillions of dollars of government bonds and mortgage-backed securities to keep interest rates low. Now amidst strong economic growth the Fed has initiated a program of “quantitative tightening,” selling off the assets it had accumulated, which by itself means higher interest rates. However, as the government allows supply to expire. The market place has to basically refi that debt. The added supply to the market place could also drive interest rates even higher than anticipated.