Is the U.S. Facing the Mother of All Bubbles?

In today's "Single Best Chart," Bloomberg's Scarlet Fu displays the gap between GDP and the Fed fund rate that suggests a coming bubble. The chart comes from Kit Juckes, Global Head of Currency Strategy at Societe Generale. Juckes notes that each of the last three significant financial bubbles in the last thirty years has been fueled by the Fed keeping interest rates below the economy's nominal growth rate.