The Kansas City Federal Reserve Regional Bank held its annual research symposium at Grand Teton National Park in Wyoming this week. The focus was on the limits of monetary policy. The challenge faced by central bankers is that since the Great Depression, the world has faced deflationary pressures from overcapacity. Oil prices have plummeted, Chinese steel floods the global markets and workers remained frustrated with low wages and finding full-time work. Central bankers have run into a problem because their primary tool of interest rate policy to stimulate the economy has run into the limit of zero nominal interest rates. At zero, they are essentially giving away money. But investment remains stuck on low. And one way to stir the economy, to prompt inflation that gives the room of rising prices for firms to make profitable investments, isn’t happening.