Market participants recognize two opposing effects of money supply growth on interest rates: a temporary liquidity effect and a permanent expectations effect. That the latter dominates in the long run is clear—a sustained increase in money growth causes proportionally higher interest rates due to a rise in inflationary expectations. In the short run, however, this interest-raising expectations effect is to some degree offset by the interest-lowering liquidity effect as monetary acceleration initially gluts the market for money balances. Depending on the relative strengths of these two opposing forces, increased money growth may lower interest rates for a while.
In the second article in this Review, "Inflationary Expectations, Money Growth, and the Vanishing Liquidity Effect of Money on Interest: A Further Investigation," Yash Mehra examines the historical response of interest rates to changes in money growth and finds that the pattern of response has changed substantially over time. During the '50s and '60s, accelerations in money growth significantly lowered interest rates in the short run through the liquidity effect. In the '70s, however, the liquidity effect was no longer significant. Triggered by high and variable rates of inflation, inflationary expectations became more responsive to changes in money growth and the expectations effect began to dominate the liquidity effect even in the short run. As a result, the temporary lowering of interest rates following an acceleration of money growth is now shorter lived and less pronounced than it was during the '50s and '60s.
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