Business Economics · Relationship between the government and the individual firm

Taxation, Subsidies and Their Effect on Firms

Updated 11 October 2026 · Fact-checked

A tax on a good raises the cost of supplying it, shifting the supply curve up by the tax per unit. Price rises and quantity falls. Buyers and sellers share the burden, called incidence, depending on elasticities. A subsidy does the opposite: supply shifts down, price falls and quantity rises.

Understand Taxation, Subsidies and Their Effect on Firms

A tax is a compulsory payment to the government. An indirect tax is charged on spending, such as GST or excise duty. The firm collects it and pays it over. A direct tax is charged on income or profit, such as income tax or corporate tax. The person or firm who earns the income pays it.

Take a per-unit (specific) tax on producers. For every unit sold, the firm must pay the government a fixed sum. At each quantity, the firm now needs a higher price to supply it. So the supply curve shifts upwards (leftwards) by the amount of the tax. Demand does not move. The new equilibrium has a higher price and a lower quantity.

Who pays is called tax incidence. It does not depend on who hands the money to the government. The price buyers pay rises, but usually by less than the tax. The firm receives the new price minus the tax. So both sides lose. The split depends on elasticity. The less elastic side bears more of the tax. If demand is inelastic (for example, fuel or medicines), consumers bear most of it. If demand is elastic, the firm bears more.

A subsidy is a payment from the government to producers or consumers. A per-unit subsidy shifts supply downwards (rightwards) by the subsidy amount. Price falls, quantity rises. The benefit is also shared. Consumers gain from the lower price. Producers gain because they receive the new price plus the subsidy. The less elastic side again gets the larger share of the benefit.

For firms, taxes raise costs and cut sales volume. Subsidies lower costs and raise output. Governments use both to raise revenue, discourage harmful goods, encourage useful goods or support incomes. A tax can also cause deadweight loss, because some trades that were worth making no longer happen.

Key rules to remember

Per-unit tax: new supply curve: If original supply is P = a + bQ, new supply is P = a + t + bQ; t is the tax per unit. The curve shifts up by t. Parallel shift for a per-unit tax.
Price received by the seller: Pseller = Pbuyer − t; At the new equilibrium, the buyer's price is higher than before. The seller keeps less than the buyer pays.
Consumer burden of a tax: Consumer burden per unit = Pbuyer(after) − P(before); Producer burden per unit = P(before) − Pseller(after). The two burdens add up to t.
Incidence split (elasticities): Consumer share ÷ Producer share = |Es| ÷ |Ed|; Es is price elasticity of supply, Ed is price elasticity of demand, at the equilibrium. This is a standard approximation for small taxes. Less elastic side bears more. In slope terms for linear curves, the consumer share of t is B ÷ (B + D), where B is the demand slope and D is the supply slope.
Government tax revenue: Revenue = t × Q(after tax); Use the new quantity, not the old one.
Per-unit subsidy: New supply: P = a − s + bQ. Subsidy cost = s × Q(after); s is the subsidy per unit. Price paid by buyer falls. Price received by seller = buyer's price + s.
Deadweight loss (linear curves): DWL = ½ × t × (Q(before) − Q(after)); Valid for linear demand and supply curves, for any size of tax. It is the area of the triangle between the curves. In the worked example, DWL = ½ × 8 × (20 − 18) = ₹8.

How to solve Taxation, Subsidies and Their Effect on Firms questions

Use the same method for any question on taxes or subsidies. Write each step down so you earn method marks.

1Identify the measure: per-unit tax, percentage tax, or subsidy. Note who pays or receives it.
2Find the original equilibrium by setting demand equal to supply. Record P0 and Q0.
3Shift the correct curve. A tax on sellers raises supply by t. A subsidy lowers it by s. If the tax is on buyers, shift demand down by t instead. The incidence is the same.
4Solve for the new equilibrium to get the new price paid by buyers and the new quantity Q1.
5Work out the price the seller keeps: buyer's price minus t for a tax, or plus s for a subsidy.
6Split the burden. Consumer burden is the rise in buyer's price. Producer burden is t minus that. For a subsidy, do the same with the fall in price.
7Calculate any extra item asked for: government revenue t × Q1, subsidy cost s × Q1, or deadweight loss.
8State the effect on the firm in words: output, price, revenue, profit and who bears the burden. Link the split to elasticity.

Quickest way: Shift, solve, split

When to use it: Use this for linear demand and supply questions where you must find prices, quantity and incidence quickly.

Write demand as P = A − BQ and supply as P = C + DQ.
For a per-unit tax t, replace C by C + t. Equate to demand: Q1 = (A − C − t) ÷ (B + D).
Buyer's price = A − B × Q1. Seller's price = buyer's price − t.
Consumer burden per unit = Buyer's price − original price P0.
Shortcut: with linear curves, the consumer's share of t is B ÷ (B + D) and the producer's share is D ÷ (B + D). The steeper curve bears more. Check that the shares add up to t.
For a subsidy s, replace C by C − s and use the same formulas.

Common mistakes in Taxation, Subsidies and Their Effect on Firms

Shifting the supply curve by the wrong amount or in the wrong direction.
Students mix up up and down, or shift by a percentage of the old price instead of the tax.
Fix: A per-unit tax adds t to the price at every quantity, so the curve moves up by t. A subsidy subtracts s. Check the direction against what should happen to quantity.
Saying consumers pay the whole tax because the firm passes it on.
Students confuse who collects the tax with who bears it.
Fix: Compute the rise in the buyer's price and compare it with t. It is usually less than t unless demand is perfectly inelastic or supply is perfectly elastic.
Calculating revenue with the old quantity.
The old quantity is easy to read from the first equilibrium.
Fix: Tax revenue is t times the quantity after the tax. Use Q1.
Mixing up which side bears more burden under elasticity.
Students remember 'elastic' and 'burden' but not the direction.
Fix: The side that finds it harder to change behaviour, the less elastic side, bears more. Inelastic demand means consumers bear more.
Treating direct and indirect taxes as the same, or classing GST as direct.
Both raise revenue, so the difference in what they tax is overlooked.
Fix: Direct taxes fall on income or wealth and are paid by the person who earns it. Indirect taxes fall on goods and services and the burden can be shifted.
Forgetting that the seller receives the buyer's price minus the tax.
Students stop after finding the new market price.
Fix: Always compute the net price the firm keeps. Profit per unit depends on it, not on the price shown on the graph.

Worked examples

Example 1

Demand for a good is P = 100 − 2Q and supply is P = 20 + 2Q, where P is in ₹. The government imposes a tax of ₹8 per unit on producers. Find the new equilibrium price paid by buyers, the price received by sellers, the quantity, the government revenue, and the consumer and producer burden.

Show the solution

Original equilibrium: 100 − 2Q = 20 + 2Q, so 80 = 4Q and Q0 = 20. P0 = 100 − 40 = ₹60.
New supply with tax: P = 28 + 2Q.
New equilibrium: 100 − 2Q = 28 + 2Q, so 72 = 4Q and Q1 = 18.
Buyer's price = 100 − 2 × 18 = ₹64.
Seller's price = 64 − 8 = ₹56.
Government revenue = 8 × 18 = ₹144.
Consumer burden per unit = 64 − 60 = ₹4. Producer burden per unit = 60 − 56 = ₹4. Total = ₹8, which equals the tax.

Answer: Buyers pay ₹64, sellers keep ₹56, quantity is 18 units, revenue is ₹144, and the tax is shared equally at ₹4 per unit each because the slopes of demand and supply are equal in size.

Example 2

Using the same demand P = 100 − 2Q and supply P = 20 + 2Q, the government instead gives a subsidy of ₹8 per unit to producers. Find the new quantity, the price paid by buyers, the price received by sellers, and the total cost to the government.

Show the solution

New supply with subsidy: P = 12 + 2Q.
Equate to demand: 100 − 2Q = 12 + 2Q, so 88 = 4Q and Q1 = 22.
Buyer's price = 100 − 2 × 22 = ₹56.
Seller's price = 56 + 8 = ₹64.
Cost to government = 8 × 22 = ₹176.
Consumer gain per unit = 60 − 56 = ₹4. Producer gain per unit = 64 − 60 = ₹4.

Answer: Quantity rises to 22 units. Buyers pay ₹56, sellers receive ₹64, and the subsidy costs the government ₹176. The benefit is shared equally at ₹4 per unit.

Exam tips

Draw a small diagram even if the question is numerical. Label the tax wedge between the buyer's price and the seller's price.
In written answers, always link incidence to elasticity and give a reason, for example necessities have inelastic demand.
For MCQs, check the direction first. A tax shifts supply left or up. A subsidy shifts it right or down.
Show the check that consumer burden plus producer burden equals the tax. It protects you from arithmetic slips.
When asked to evaluate, mention deadweight loss, revenue raised, and effects on firm profit and output.

Practice questions from Relationship between the government and the individual firm

Taxation, Subsidies and Their Effect on Firms: frequently asked questions

What is tax incidence?

Tax incidence is the way the burden of a tax is shared between buyers and sellers. It does not depend on who legally pays the government. It depends on the relative elasticities of demand and supply.

How does a tax on producers affect the supply curve?

A per-unit tax shifts the supply curve upwards by the amount of the tax. At every quantity, producers need a higher price to cover the tax. The new equilibrium has a higher price and lower quantity.

What is the difference between direct and indirect taxes?

A direct tax is charged on income or wealth and paid by the person or firm who earns it, such as income tax. An indirect tax is charged on goods and services, such as GST, and the burden can be passed on through prices.

Who benefits more from a subsidy?

The benefit is shared between consumers and producers. The side with the less elastic curve gets the larger share. A subsidy lowers the price paid by buyers and raises output.