In the pantheon of famous economists, Knut Wicksell is hardly a household name. Unlike Adam Smith, the Swedish interest-rate expert never made it to the face of a banknote. In 1898, Wicksell shared the idea that inflation and economic instability stem from an imbalance: It occurs when market interest rates (set by the Fed and by banks) are out of sync with "the natural rate of interest." The U.S. economy is so strong that its natural rate is far above its official rates, which is why interest on American debt is relatively low given its size. "To oversimplify: You could argue that U.S. deficits are, in effect, being increasingly funded by its tech sector."