Market Equilibrium

Test yourself

Market Equilibrium

The equilibrium is the point where the demand curve meets the supply curve.

Equilibrium price

This is the only price where the amount consumers want to buy is equal to the amount producers want to sell.
If the market is at equilibrium, there is no reason to move away.
Supply and demand (market forces) dictate the equilibrium quantity and price in a free market.

Disequilibrium

Disequilibrium is when the market is not at a stable price and quantity.
If the market is not at equilibrium, economic pressure arises to move the market towards a stable price and quantity.
- E.g if petrol prices were to rise above their equilibrium level, the market would respond and the quantity demanded would fall.

Excess supply and demand

Excess supply and demand occur at disequilibrium.
The higher price makes it more profitable for petrol producers, so output expands.
The difference between the quantity demanded and quantity supplied is now the excess supply.
When quantity demanded exceeds quantity supplied, there is excess demand.

Pressure to reach equilibrium

The market price is unstable when there is excess demand or supply.
Excess supply will force producers to cut the price because it is better to sell at a lower price than not at all. Others will follow.
Excess demand will signal to producers they can generate more profit by raising the price and will do so.
So excess demand and supply can lead to price change.

Equilibrium vs Disequilibrium in a Market

Equilibrium is a state of rest, where price and quantity are stable. In disequilibrium, there is pressure from market forces to reach equilibrium.

Equilibrium

The point of equilibrium is determined by the forces of demand and supply in an economy. These are called market forces. Here, supply is equal to demand.
This model of equilibrium assumes perfect competition. It also assumes ceteris paribus (everything else equal), as well as independence between supply and demand.

Disequilibrium

At disequilibrium, price and quantity are not stable.
Market forces will move the economy back to a position of stability at equilibrium over time.

Shifts in Equilibrium

Demand and supply curve shifts affect where an equilibrium is.

Demand curve shifts

A shift in the demand curve (but not in the supply curve) will have the following effects:
- An increase in demand (D->D1) will cause an increase in price. Supply will extend and form a new equilibrium (Q1,P1).
- A decrease in demand (D->D2)will cause the price to fall. Supply will contract and form a new equilibrium (Q2, P2).

Supply curve shifts

A shift in the supply curve (but not in the demand curve) will have the following effects:
- An increase in supply (S->S1)will cause a decrease in price. Demand will extend and form a new equilibrium (Q1,P1).
- A decrease in supply (S->S2) will cause an increase in price. Demand will contract and form a new equilibrium (Q2,P2).

Elasticity (slopes of demand and supply curves)

Price elasticity of demand and supply affect how much the equilibrium price and quantity change by.
- E.g a rightward shift in the demand curve along an elastic supply curve will influence quantity more than price.
- An inelastic demand curve is steeper than an elastic demand curve.

1Microeconomics

1.1Competitive Markets: Demand & Suply

1.1.1Markets & Demand

1.1.2Diminishing Marginal Returns

1.1.3Supply

1.1.4Market Equilibrium

1.1.5Price Mechanism

1.1.6Consumer & Producer Surplus

1.1.7IB Multiple Choice - Demand

1.1.8IB Multiple Choice - Supply

1.2Elasticity

1.2.1Elasticities of Demand

1.2.2Factors Affecting Price Elasticity of Demand

1.2.3Elasticity of Supply

1.2.4Price Elasticity of Supply

1.2.5IB Multiple Choice - Price Elasticity of Demand

1.2.6IB Multiple Choice - Price Elasticity of Supply

1.2.7IB Multiple Choice - Other Elasticities

1.3Government Intervention

1.3.1Indirect Taxes & Subsidies

1.3.2Application Question - Taxing Prices or Quantities

1.3.3Subsidies & Price Controls

1.3.4Deadweight Loss & Government Intervention

1.3.5Elasticity & Tax Incidence

1.3.6IB Multiple Choice - Government Intervention

1.4Market Failure

1.4.1Types of Market Failure

1.4.2Introduction to Externalities

1.4.3Negative Externalities

1.4.4Policy for Negative Externalities

1.4.5Positive Externalities

1.4.6The Deadweight Welfare Loss of Externalities

1.4.7Case Study - The Externalities of Education

1.4.8Public Goods & the Free-Rider Problem

1.4.9Asymmetric Information

1.4.10End of Topic Test - Market Failure

1.4.11Application Questions - Market Failure

1.5HL: Theory of the Firm & Market Structures

1.5.1Theory of the Firm & Market Structures

2Macroeconomics

2.1The Level of Overall Economic Activity

2.1.1The Circular Flow of Income

2.1.2Defining GDP

2.1.3Limitations of GDP

2.1.4IB Multiple Choice - Economic Indicators

2.1.5Business Cycles

2.1.6Output Gaps

2.2Aggregate Demand & Aggregate Supply

2.2.1The Aggregate Demand Curve

2.2.2Components of Aggregate Demand

2.2.3Shape of the Aggregate Demand Curve

2.2.4Shifts in Aggregate Demand

2.2.5IB Multiple Choice - Aggregate Demand

2.2.6Short & Long-Run Aggregate Supply

2.2.7Alternative Models of LRAS

2.2.8Equilibrium in the AD-AS Model

2.2.9Output Gaps & the AD-AS Model

2.3Macroeconomic Objectives

2.3.1Introduction to Unemployment

2.3.2Limitations of Unemployment

2.3.3Types of Unemployment

2.3.4Causes & Impact of Unemployment

2.3.5Defining Inflation

2.3.6Measuring Inflation

2.3.7Use of Index Numbers

2.3.8The Consumer Price Index

2.3.9Consequences of Inflation

2.3.10Causes of Inflation

2.3.11Inflation & Unemployment Tradeoff

2.3.12The Short-Run Phillips Curve

2.3.13The Long-Run Phillips Curve

2.4Economic Growth, Poverty & Inequality

2.4.1Measuring Economic Growth

2.4.2Determinants of Productivity

2.4.3Economic Growth & Productivity

2.4.4Absolute & Relative Poverty

2.4.5Inequality

2.4.6Inequality 2

2.4.7Lorenz Curve

2.4.8Government Policy on Poverty

2.4.9End of Topic Test - Poverty & Inequality

2.4.10Application - Inequality & Poverty

2.5Fiscal Policy

2.5.1Introduction to Fiscal Policy

2.5.2Fiscal Policy and AD-AS Model

2.5.3Fiscal Policy Lags

2.5.4Automatic Stabilizers

2.5.5IB Multiple Choice - Fiscal Policy

2.6Monetary Policy

2.6.1Objectives of Monetary Policy

2.6.2Monetary Policy Implementation

2.6.3Monetary Policy & AD-AS Model

2.6.4Monetary Policy Lags & Pitfalls

2.7Supply-Side Policies

2.7.1Supply-Side Policies

2.7.2Supply-Side Policies 2

3The Global Economy

3.1International Trade

3.1.1Globalisation

3.1.2Globalisation for LEDCs

3.1.3Globalisation for MEDCs

3.1.4Comparative Advantage & Trade

3.1.5Protectionism

3.1.6Arguments for Protectionism

3.1.7Arguments Against Protectionism

3.1.8End of Topic Test - Globalisation & Trade

3.1.9Case Study - Globalisation & Trade

3.2Exchange Rates

3.2.1Floating Exchange Rates

3.2.2Fixed Exchange Rate

3.2.3Effect of a Stronger & Weaker Dollar

3.3The Balance of Payments

3.3.1Balance of Payments

3.3.2Balance of Payments 2

3.3.3FDI & Reducing a BoP Deficit

3.4Economic Integration

3.4.1Customs Unions & WTO

3.4.2Merged Currency

3.5Terms of Trade

3.5.1Absolute & Comparative Advantage

3.5.2Gains from Trade

3.5.3Terms of Trade

3.5.4IB Multiple Choice - Comparative Advantage & Trade

3.6Economic Development

3.6.1Factors Influencing Growth & Development

3.6.2International Institutions

3.6.3Measures of Development

3.6.4Barriers to Development

3.6.5Case Study - The Bottom Billion

3.6.6End of Topic Test - Emerging & Developing

3.7The Role of Domestic & International Factors

3.7.1Interventionist Strategies

3.7.2Development Strategies

3.7.3Development Promotion Policies

3.7.4End of Topic Test - Growth & Global Development

3.7.5Application Questions -Growth & Global Development

3.8The Role of International Trade

3.8.1International Institutions

3.8.2End of Topic Test - Globalisation & Trade

3.9The Role of Foreign Aid

3.9.1Aid

3.9.2Limitations of Aid

3.9.3Support for Aid

3.9.4Application Questions - Developing Countries

Jump to other topics