interest rate: Nonlinear Function
Created: February 08, 2022
Modified: October 09, 2022

interest rate

This page is from my personal notes, and has not been specifically reviewed for public consumption. It might be incomplete, wrong, outdated, or stupid. Caveat lector.

It's a bit counterintuitive that high interest rates prevent inflation. After all, doesn't a high interest rate mean that the central bank must create money at a faster rate, in order to pay the interest?

This would be true, if we only looked at the portion of the money supply held as central bank reserves (sometimes called 'MB'). But this is a very small fraction of the overall money supply - as of 2022 the reserve requirement for US bank deposits is just 10%, and bank deposits themselves (the 'M1' money supply) are a small fraction of dollar-denominated assets. So we need to look at the effect of interest rates on the rest of the money supply.

Almost all of the extended money supply consists of money created by loans (IOUs are money), and central bank interest rates are effectively a lower bound on the interest charged for loans (no bank would ever fund a risky loan at a rate lower than what they can get risk-free from the central bank). When borrowing money becomes expensive, fewer people will do it, so the amount of loan-created money decreases. This indirect deflationary effect dwarfs the direct inflationary effect on the MB supply.

Natural rate: There's a notion in economics of the 'natural' or neutral interest rate (Wicksell, 1898):

There is a certain rate of interest on loans which is neutral in respect to commodity prices, and tends neither to raise nor to lower them.