In a two sector closed economy, deficiency of Aggregate Demand (AD) occurs largely due to two factors:
- Reduction in private consumption expenditure : Private expenditure is an important component of AD. Reduction in private consumption expenditure causes a serious deficiency in AD. Private consumption expenditure may reduce owing to several reasons. However, the most important is reduction in propensity to consume or increase in propensity to save.
- Reduction in Investment Expenditure : Investment expenditure is the other important component of AD. Any reduction in investment expenditure implies a reduction in AD. Investment expenditure may reduce in situations of poor business expectations. It happeed in all market economies of the world in 2009.
In a four sector open economy, the following factors also contribute to the deficiency of AD:
- Reduction in Government Expenditure : Government expenditure is of vital significance in welfare economies. However, there could be situations when public enterprises pile up huge losses owing to their inefficiencies. In such situations, instead of making frsh investments, the government may resort to disinvestment.
- Decline in Exports : Decline in exports may occur due to lack of demand in rest of the world. We know, exports are an important component of AD. A fall in exports implies a fall in expenditure on the domestically produced goods and services.
- Rise in Imports : Imports may rise when international prices are lower than the domestic prices. We know, imports are a negative component of AD. Accordingly, a rise in imports leads to a fall in AD.
- Increase in Tax Rates : Increase in tax rates leaves lesser disposable income with the people. It reduces their capacity to spend, even when their propensity to spend remains the same. Lower disposable income means lower level of AD