Microeconomics Study Notes: Taxes and Subsidies in Competitive Markets

Chapter 7: Taxes and Subsidies

Introduction to Taxes and Subsidies

This chapter examines the economic impact of unit taxes and unit subsidies in competitive markets. It focuses on how these government interventions affect market efficiency, production, costs, prices, and the distribution of tax burdens between consumers and producers.

Unit Taxes: Definitions and Concepts

• Unit Tax: A fixed amount of tax imposed on each unit of a good or service sold.

• Tax Incidence: The share of a tax ultimately paid by consumers and sellers. It determines who bears the economic burden of the tax.

• Statutory Incidence: Indicates who is legally responsible for paying the tax to the government (either buyers or sellers).

• Economic Incidence: Refers to the change in the distribution of real income induced by a tax, regardless of statutory responsibility.

• Buyers' Response: Buyers respond to the price with the tax, as this is the price they must pay.

• Sellers' Response: Sellers respond to the price without the tax, as this is the price they receive.

Graphical Analysis of Taxes

Taxes create a wedge between the price buyers pay and the price sellers receive. This wedge is equal to the amount of the tax.

• Perceived Demand Curve (with tax on buyers): The demand curve shifts downward by the amount of the tax. If the original demand is $P^D = 110 - \frac{Q}{100}$ and the tax is $t$, the perceived demand is $P^P = P^D - t$.

• Perceived Supply Curve (with tax on sellers): The supply curve shifts upward by the amount of the tax. If the original supply is $P^S = 10 + \frac{Q}{150}$ and the tax is $t$, the perceived supply is $P^S = P^S + t$.

Example: Tax on Hats

• Original supply: $P^S = 10 + \frac{Q}{150}$

• Original demand: $P^D = 110 - \frac{Q}{100}$

• With a $20 tax on buyers:$P^P = 90 - \frac{Q}{100}$

• With a $20 tax on sellers:$P^S = 30 + \frac{Q}{150}$

Important Point: The economic incidence of a unit tax is independent of whether it is levied on consumers or producers. The division of the tax burden depends on the price elasticities of supply and demand.

Elasticity and Tax Incidence

• Tax Wedge: The difference between the price paid by consumers and the price received by producers due to the tax.

• Elasticity of Demand and Supply: The more elastic the demand or supply, the less of the tax burden that side bears.

• Perfectly Inelastic Demand: Consumers pay the entire tax.

• Perfectly Elastic Demand: Sellers pay the entire tax.

• Perfectly Inelastic Supply: Sellers pay the entire tax.

• Perfectly Elastic Supply: Consumers pay the entire tax.

Table: Tax Incidence and Elasticity

Elasticity Condition	Who Pays the Tax?
Perfectly Inelastic Demand	Consumers pay all
Perfectly Elastic Demand	Sellers pay all
Perfectly Inelastic Supply	Sellers pay all
Perfectly Elastic Supply	Consumers pay all
Unit Elasticity (both sides)	Tax is shared

Taxes and Market Efficiency

• Taxes generally reduce market efficiency by causing the quantity traded to fall below the allocatively efficient level.

• Without a tax, marginal social benefit equals marginal social cost, and total surplus (consumer + producer surplus) is maximized.

• With a tax, total surplus decreases due to the creation of deadweight loss—the loss of surplus that neither consumers nor producers receive.

Principles of Tax Fairness

• Ability-to-Pay Principle: People should pay taxes according to how easily they can bear the burden.

• Benefits Principle: People should pay taxes equal to the benefits they receive from government services.

Unit Subsidies: Definitions and Effects

• Subsidy: A payment made by the government to a producer or seller when a good is sold.

• A subsidy increases supply by transferring some production costs to the government.

• Subsidies lower the price paid by buyers and raise the price received by sellers.

• Both consumer and producer surplus increase, but the total cost of the subsidy exceeds the combined surplus gains, resulting in deadweight loss.

Table: Effects of Subsidy

Effect	Result
Supply	Increases (shifts right)
Price paid by buyers	Decreases
Price received by sellers	Increases
Consumer surplus	Increases
Producer surplus	Increases
Deadweight loss	Occurs (cost of subsidy > surplus gains)

Summary Equations

• Tax Burden on Consumers: $P_{buyers} - P_{equilibrium}$

• Tax Burden on Sellers: $P_{equilibrium} - P_{sellers}$

• Deadweight Loss from Tax: $\frac{1}{2} \times \text{Tax} \times (Q_{equilibrium} - Q_{tax})$

• Deadweight Loss from Subsidy: $\frac{1}{2} \times \text{Subsidy} \times (Q_{subsidy} - Q_{equilibrium})$

Example Application

• Suppose a $20$unit tax is imposed on hats. The supply and demand equations shift as shown above, and the new equilibrium quantity and prices can be solved by setting the perceived supply and demand equal and solving for$Q$and$P$.

• Similarly, a subsidy on corn increases supply, lowers the price for buyers, and raises the price for sellers, but creates deadweight loss.

Additional info: These notes expand on the provided slides and images by including formal definitions, equations, and tables for clarity and completeness. All graphical relationships and economic principles are explained in academic context for microeconomics students.