## Perfect Competition 2 - Lump-Sum, Tax & Subsidy

I have been tutoring some lately and have noticed that many students seem to have a bit of trouble with Lump-Sum & PerUnit taxes and subsidies within a perfect competitive market structure. While I have only seen this in one FRQ,, I believe 2008, Question, 1, I want to try and explain it and then we will do the 2008 FRQ and see if our graphs help us understand and answer the question...

Lump Sum Tax --A lump sum tax is a tax of a fixed amount that has to be paid by everyone (every firm in the industry) regardless of the level of his or her (its) income (production). (So no matter how much you produce or don't produce, you still have to pay this tax).

Lump Sum Subsidy - A lump sum subsidy of a fixed amount that is given to everyone (every firm in the industry).  Think of a subsidy like a gift or grant from the government for producing in the specified industry.

Subsidy humor

Lump-Sum Subsidy

So, Short-run is on the left and Long-run is on the right.

Marginal Cost curves intentionally left off (as not effected) to show effects clearly,, feel free to add as Profit Max is where MR=MC.

Lets start with the short-run. The market graph is drawn showing supply and demand in equilibrium. Firms look at lump-sum subsidies as if they are monies added, decreasing the firms fixed costs. Additional decreases in fixed costs will not effect the variable costs and therefore won't effect marginal costs. Fixed cost increases will effect the ATC or (Average total costs curve) not the AVC or MC curves.
• A lump sum subsidy will shift the ATC downward, in the short-run the firm will earn positive (super/abnormal) economic profits due to the subsidy. Remember - that in the short run other firms cannot enter the market.
• In the long-run firms are attracted to this industry's abnormal profits and will enter the market. As more producing firms enter the market, supply increases,  pushing down the market price and increasing the quantity produced. In the long run the the price will decrease to the point that the firm is only making normal profit/zero economic profit.
Lump-Sum Tax

So, Short-run is on the left and Long-run is on the right.

Lets start with the short-run. The market graph is drawn showing supply and demand in equilibrium. Firms look at lump-sum taxes as if they are extra costs added to the firms fixed costs. Increases in fixed costs will not effect the variable costs and therefore will not shift the marginal cost curve.
• A lump sum tax will shift the ATC upward, in the short-run the firm will have a loss due to the tax. Remember - that in the short run other firms cannot enter the market.
• In the long-run firms exit this industry. As more producing firms exit the market, supply decreases,  pushing up the market price and decreasing the quantity produced. In the long run the the price will increase to the point that the firm is only making normal profit/zero economic profit.
AP Microeconomics 2008, FRQ, question 1

So, (a) is asking for the short run market graph in equilibrium,, and the long run firm graph,, labelled appropriately, of course. This question is starting with everything in equilibrium.

(b) Notice, the underlined in the short-run.
(i) Callahan's quantity of output? (Callahan's output/quantity doesn't change in the short-run as lump-sum subsidies are considered as an increase in fixed costs and therefore don't effect output/quantity produced.) (Variable costs are not effected therefore marginal cost is not effected.)
(ii) Callahan's Profit? (Callahan's profit definitely increases in the short-run)
(iii) The number of firms in the industry? (Tricky bastards) (The number of firms in the short-run never changes, look at the market graph in the short-run,,, firms only enter and exit in the long run.)

(c) Notice, the underlined in the long run.
(i) The number of firms in the industry. Explain (In the long-run the number of firms enter the market attracted to Callahan's abnormal profits) (Look at the long-run market graph.)
(ii) Price? (The price decreases as new firms increase supply, pushing down the price.)
(iii) Industry Output? (Industry output will increase.) (Look at the long-run firm graph and notice that the quantity is now at Q2, this makes since in that at the new lower price more quantity will be demanded and supplied by the firms in the industry.)

AP 2008 FRQ, Question 1 - Scoring Guideline

Both graphs in one,, for your learning pleasure.