Money.
The relationship between the money supply and the price level is that the amount of money in circulation in an economy has a direct impact on the aggregate price level. This is mainly because the abundance of money leads to an increase in the demand for goods and services, while the scarcity of money has the opposite effect. In economic terms, this effect is explained by the quantity theory of money, which states that the amount of money offered in an economy has a direct influence on the price level.
A simple way to see the relationship between the money supply and the price level is to consider the fact that consumers will only spend when they have something to spend. That is, when there is a lot of money in the economy, people will have more to spend. This increase in demand also causes a corresponding increase in the price level. Excess liquidity leads to a situation where a lot of money will compete for an often limited supply of goods. This causes money to gradually lose its value, which consequently leads to price increases.
Economists rely on the relationship between the money supply and the price level as one of the indicators of the state of the economy. When there is an increase in the aggregate price, one of the main responsible factors is the excess demand by the consumer with easy access to cash. The government’s response to this is usually the introduction of monetary or fiscal policies intended to restrict the ease with which consumers can obtain money, including bank loans and various types of credit. One method by which the government can restrict access to money is through increases in general interest rates.
The effect of this restriction further illustrates the relationship between the money supply and the price level, because this maneuver usually forces the price level down. When a country’s central bank raises interest rates, consumers may find the terms for obtaining cash prohibitively expensive or too stringent, as other banks tighten their lending policies in response to rising interest rates. As a consequence of the lack of easy access to resources, consumers tend to become more conservative in their consumption habits, leading to a drop in demand for goods and services. The consequence of a reduction in demand is a concomitant fall in the prices of goods and services.