Econ 101: Interest rates

President Trump wants the Federal Reserve to lower interest rates thinking that that would reduce the interest the Federal Government pays in interest on its debt, which this last year was $1.13 trillion (yes trillion). Prior to 2008, the Fed’s policy interest rate—the so called Fed funds rate—was the overnight rate on overnight (i.e. one day) loans between banks. I will skip how the Fed determines (brings about in the market) that rate. Since 2008, when the Fed started to pay interest on bank reserves (deposits at Federal Reserve Banks), the Fed’s policy rate has been the rate paid on bank reserves.

The interest rates paid on longer (than overnight) loans (e.g., one, two, ten-year bonds) are related to the overnight rate because rolling over overnight loans for ten years is an alternative to a ten-year bond. This note explains that relationship.

The interest rate on, say, a one-year bond reflects what the market (lenders and borrowers) expects the one-day rate to be each day over that period. That, in turn, depends on what the market expects the “real” rate to be plus the rate of inflation. Market rates reflect the real rate plus the inflation rate. If inflation increase, other things equal, market interest rates increase.

So, the interest rate on a ten-year bond will reflect what the market expects the overnight rate to be over the next ten years, which reflects the expected real rate and the expected inflation rate over that period. So what happens to interest rates (say the ten-year bond rate) when the Fed lowers its policy rate as President Trump wants? It depends primarily on what that does to the market’s expectation of inflation over the relevant future period.

On Wednesday Dec 10 the Fed reduced its policy rate .25% to 3.50 to 3.75%. On that day the ten-year bond rate fell from 4.19% the day before to 4.15% but by Friday (two days later) had returned to 4.18% In short the ten year Treasury bond rate is essentially unchanged by the quarter percent drop in the Fed’s policy rate. Why? Because the market expects the drop in the overnight rate to be largely offset by a slight increase in inflation over the next ten years.

If the Fed is correct that lowering its policy rate is appropriate for continuing the reduction of inflation to its 2% target, then the ten-year rate will fall as well. Clearly an excessive cut in the policy rate (one that increases the expected rate of inflation) will increase longer term interest rates rather than lower them. Class dismissed.