Marginal Propensity To Import - MPM

What is the 'Marginal Propensity To Import - MPM'

The marginal propensity to import (MPM) is the amount imports increase or decrease with each unit rise or decline in disposable income. The marginal propensity to import is thus the change in imports induced by a change in income. An economy with a positive marginal propensity to consume is likely to have a positive marginal propensity to import. This is because a portion of goods consumed is likely to be imported.

MPM is calculated as dIm/dY, meaning the derivative of the import function (Im) with respect to the derivative of the income function (Y).

BREAKING DOWN 'Marginal Propensity To Import - MPM'

If the marginal propensity to import is 0.3, then an increase in income of $1 will result in an increase in imports of $0.30 ($1 x 0.3).

Countries that consume more imports as their incomes rise have a significant impact on global trade. If a country that imports significant amounts of goods runs into a financial crisis, the extent to which that country’s economic woes will impact exporting countries depends on its marginal propensity to import and the makeup of the goods imported. The level of negative impact on imports from falling income is greater when a country has a marginal propensity to import greater than its average propensity to import. This gap results in a higher income elasticity of demand for imports, leading to a drop in income resulting in a more than proportional drop in imports. 

Countries that have sufficient natural resources within their borders and have developed markets typically have lower marginal propensities to import. Countries that are dependent on imports have a higher marginal propensity to import.


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