Lower inflation and inflationary-expectations in the US...

Interest-rate depends upon the money-supply, the price level and expectation of changes in it, because of the price-stability objective of the monetary-policy or the central-banks. They manage money-supply to adjust interest-rate and demand/supply which jointly determines the price-level or inflation. But, interest-rate in turn is also determined by inflation and inflationary expectations, both short-run and long-run. Higher inflation and inflationary expectations also make the central-banks fine-tune money-supply and interest-rate. Normally central-banks job is to ensure price-stability, but when growth-rate is tumbling it might set higher-inflation-targets, because it is a sign of higher demand/supply and economic-activity. Generally, booms and high growth-rates coincide with higher prices and interest-rate. Nonetheless, busts and slow-downs in the economic-activity and growth-rate calls for lower interest-rates, but to cut interest-rates during down-turn it is important to tighten during higher inflation otherwise it would feed bubbles by increasing the gap between nominal and real prices of assets because of inflation. The fear that lose money-supply and interest-rate might create asset-price-bubbles in the US is baseless since inflation is too low. Moreover, the fear of risky investment because of too low rates is again overdone since banks lend only after assuring feasibility of the project. Nevertheless, low interest-rate on retirement-funds also depends on inflation and inflationary expectation, and, low interest-rate would also mean that inflation in future could remain low which means higher real-interest rates, and the argument that pension funds might lose because of low rates may also be overblown because it would also signal that inflation could remain low in the future so that less savings would be needed. In the US economy low inflation is responsible for low interest-rates which may push the case for more money-supply since it has been a year now when the Fed ended its QE program and inflation is still below the official target of 2%. The effect of QE is fading since inflationary expectations are still low with oil from the Shale-revolution, which had put the expansion of the US economy in shambles many times before. Lower oil-price expectations in the economy has kept inflationary expectations and interest rate low,  which is likely to stay because the US is now a big oil producing country. Most of the prior recessions in the US economy were associated with oil-price booms and inflation. Lower oil-prices are a major contributor to low inflation and inflationary expectations after Shale. Higher oil-prices in the future would also make high-cost shale-exploration more viable, and, thereby more production and supply leading to further low oil prices, inflation expectations and interest-rate.