Chapter 7 β Production, Costs, and Industry Structure
Every firm, from a pizza shop to Amazon, must convert inputs into outputs and manage costs to earn a profit. This chapter explores how firms produce, how costs behave in the short run vs. the long run, and how the shape of cost curves determines the structure of entire industries.
Table of Contents
Glossary of Key Terms
| Term | Definition | |ββ|ββββ| | Explicit costs | Out-of-pocket payments (wages, rent, materials) | | Implicit costs | Opportunity cost of resources the firm already owns | | Accounting profit | Total revenue β explicit costs | | Economic profit | Total revenue β (explicit + implicit costs) | | Production function | Equation showing how inputs map to output: $Q = f(L, K)$ | | Fixed inputs | Factors that cannot change in the short run (e.g., capital) | | Variable inputs | Factors that can change quickly (e.g., labor, materials) | | Total product (TP) | Total output at a given level of inputs | | Marginal product (MP) | Additional output from one more unit of input: $MP = \Delta TP / \Delta L$ | | Diminishing marginal product | After some point, each additional worker adds less output | | Fixed costs (FC) | Costs that do not change with output level | | Variable costs (VC) | Costs that increase with output | | Total cost (TC) | FC + VC | | Marginal cost (MC) | Cost of producing one more unit: $MC = \Delta TC / \Delta Q$ | | Average total cost (ATC) | $TC / Q$ β typically U-shaped | | Average variable cost (AVC) | $VC / Q$ β always below ATC | | Economies of scale | Larger output β lower average cost (LRAC slopes down) | | Constant returns to scale | Larger output β same average cost (LRAC is flat) | | Diseconomies of scale | Larger output β higher average cost (LRAC slopes up) | | LRAC curve | Long-run average cost; envelope of all possible SRAC curves | | SRAC curve | Short-run average cost for a given level of fixed costs | | Production technology | A specific combination of labor, capital, and technique |
1. Explicit & Implicit Costs and Profit
1.1 Revenue and Cost Basics
\[\text{Profit} = \text{Total Revenue} - \text{Total Cost}\] \[\text{Total Revenue} = P \times Q\]Total cost is everything the firm pays to produce and sell its products. It comes in two flavors:
Explicit costs β actual out-of-pocket payments: wages, rent, raw materials, utilities, etc.
Implicit costs β the opportunity cost of using resources the firm already owns. No cash changes hands, but a real sacrifice is made.
Common implicit costs include:
- Foregone salary β the owner could earn elsewhere
- Foregone rent β using owned property for the business instead of renting it out
- Foregone interest β using personal savings instead of investing them
- Foregone leisure β working extra hours without additional pay
1.2 Accounting Profit vs. Economic Profit
| Concept | Formula | What It Measures |
|---|---|---|
| Accounting profit | Revenue β Explicit costs | Cash-based profit (used for taxes) |
| Economic profit | Revenue β (Explicit + Implicit costs) | True economic success |
Key insight: A firm can have positive accounting profit but negative economic profit. This means the owner would be better off doing something else with their resources.
Worked Example β Erynβs Law Practice
Eryn considers leaving her $125,000/year corporate job to open her own practice.
| Item | Amount |
|---|---|
| Expected revenue | $200,000 |
| Office rent (explicit) | β$50,000 |
| Law clerk salary (explicit) | β$35,000 |
| Total explicit costs | $85,000 |
| Accounting profit | $200,000 β $85,000 = $115,000 |
| Foregone corporate salary (implicit) | β$125,000 |
| Economic profit | $200,000 β $85,000 β $125,000 = β$10,000 |
Erynβs accounting profit is strong ($115k), but her economic profit is negative (β$10k). She would earn $10,000 less than staying at the corporate firm.
2. Production in the Short Run
2.1 The Production Function
A production function is a mathematical relationship showing how much output a firm can produce given different amounts of inputs:
\[Q = f(\text{Labor}, \text{Capital}, \text{Natural Resources}, \text{Technology})\]In simplified short-run form: $Q = f(L)$ since capital $K$ is fixed.
2.2 Factors of Production
| Factor | Description | Examples |
|---|---|---|
| Natural Resources (Land) | Raw materials, land | Flour, tomatoes, wood, natural gas |
| Labor | Human effort (physical + mental) | Pizza maker, counter staff, barbers |
| Capital | Physical equipment and buildings | Oven, peel, factory, computers |
| Technology | The process for producing output | Recipes, procedures, methods |
| Entrepreneurship | Decision-making and risk-taking | Business owner, founder |
2.3 Fixed vs. Variable Inputs
| Type | Definition | Examples | Time Horizon |
|---|---|---|---|
| Fixed inputs | Cannot easily change in the short run | Building, lease, machinery | Bound by contracts/physical limits |
| Variable inputs | Can be increased or decreased quickly | Workers, raw materials | Adjustable day-to-day |
- Short run β at least one factor of production is fixed (typically capital)
- Long run β all factors are variable; the firm can change everything including plant size
2.4 Total Product and Marginal Product
\[MP = \frac{\Delta TP}{\Delta L}\]Lumberjack Example (two-person crosscut saw, K = 1 saw)
| # Lumberjacks | 1 | 2 | 3 | 4 | 5 |
|---|---|---|---|---|---|
| Trees cut (TP) | 4 | 10 | 12 | 13 | 13 |
| Marginal Product | 4 | 6 | 2 | 1 | 0 |
- 1 β 2 workers: MP increases from 4 to 6 (the saw works better with two people)
- 2 β 3 workers: MP drops to 2 β diminishing marginal returns begin
- 4 β 5 workers: MP = 0, adding a 5th worker adds nothing
2.5 Law of Diminishing Marginal Product
Law of Diminishing Marginal Product: As a firm employs more of a variable input (holding other inputs fixed), eventually the marginal product of that input declines.
Why does it happen? Because capital is fixed. More workers share the same equipment, so each additional worker has less capital to work with and contributes less output.
Diminishing marginal product β negative product. Output can still be rising (TP increasing) even as marginal product falls. Only when MP becomes negative does total product actually decline.
3. Costs in the Short Run
3.1 From Production Function to Cost Function
Every input has a factor payment:
- Raw materials β prices
- Land/buildings β rent
- Labor β wages & salaries
- Financial capital β interest & dividends
- Entrepreneurship β profit (residual)
To find costs: invert the production function to find how many workers are needed for each output level, then multiply by the wage rate.
Widget Example
| Widgets (Q) | 1 | 2 | 3 | 4 |
|---|---|---|---|---|
| Workers needed (L) | 3.25 | 4.4 | 5.2 | 9 |
| Γ Wage ($10/hr) | $32.50 | $44.00 | $52.00 | $90.00 |
Notice the jump from Q=3 to Q=4 β diminishing marginal productivity means it takes many more workers (and much more cost) to squeeze out that last unit.
3.2 Fixed, Variable, and Total Costs
\[TC = FC + VC\]| Cost Type | Behavior | Example |
|---|---|---|
| Fixed cost (FC) | Constant regardless of output | Rent, machinery, insurance |
| Variable cost (VC) | Rises with output | Labor, raw materials |
| Total cost (TC) | FC + VC | Sum of all costs |
Sunk costs: Fixed costs are often sunk costs β already spent and irrecoverable. In making forward-looking decisions, firms should generally ignore sunk costs and focus on variable and marginal costs.
3.3 Average and Marginal Costs
| Measure | Formula | Shape | Interpretation |
|---|---|---|---|
| Average Total Cost (ATC) | $TC / Q$ | U-shaped | Cost per unit on average |
| Average Variable Cost (AVC) | $VC / Q$ | U-shaped (below ATC) | Variable cost per unit |
| Average Fixed Cost (AFC) | $FC / Q$ | Always falling | βSpreading the overheadβ |
| Marginal Cost (MC) | $\Delta TC / \Delta Q$ | Generally rising | Cost of the next unit |
The Clip Joint Barbershop (Fixed cost = $160/day, wage = $80/barber)
| Labor | Quantity | FC | VC | TC | MC | ATC | AVC | |ββ-|βββ-|ββ|ββ|ββ|ββ-|ββ-|ββ-| | 1 | 16 | $160 | $80 | $240 | $5.00 | $15.00 | $5.00 | | 2 | 40 | $160 | $160 | $320 | $3.33 | $8.00 | $4.00 | | 3 | 60 | $160 | $240 | $400 | $4.00 | $6.67 | $4.00 | | 4 | 72 | $160 | $320 | $480 | $6.67 | $6.67 | $4.44 | | 5 | 80 | $160 | $400 | $560 | $10.00 | $7.00 | $5.00 | | 6 | 84 | $160 | $480 | $640 | $20.00 | $7.62 | $5.71 |
3.4 The MCβATC Relationship
The Grades Analogy: Think of MC and ATC like quiz scores and your running average:
- If your next quiz score (MC) is below your current average (ATC), it pulls the average down β ATC is falling
- If your next quiz score (MC) is above your current average (ATC), it pulls the average up β ATC is rising
- MC crosses ATC at ATCβs minimum point
Key relationships:
- When $MC < ATC$: ATC is falling (MC pulls average down)
- When $MC > ATC$: ATC is rising (MC pulls average up)
- When $MC = ATC$: ATC is at its minimum β the most efficient per-unit cost
Diagram β U-Shaped Cost Curves (MC, ATC, AVC):
3.4a Algebraic Cost Function Analysis
Worked Example β Deriving All Cost Curves from a TC Function:
Given: $TC = 200 + 10Q + 0.5Q^2$ (where FC = 200)
Derive every cost measure:
| Measure | Formula | Derivation |
|---|---|---|
| FC | 200 | The constant term |
| VC | $10Q + 0.5Q^2$ | TC β FC |
| ATC | $\frac{200}{Q} + 10 + 0.5Q$ | TC / Q |
| AFC | $\frac{200}{Q}$ | FC / Q |
| AVC | $10 + 0.5Q$ | VC / Q |
| MC | $10 + Q$ | $\frac{dTC}{dQ}$ (derivative of TC) |
Finding minimum ATC: Set MC = ATC:
\[10 + Q = \frac{200}{Q} + 10 + 0.5Q\] \[0.5Q = \frac{200}{Q} \implies Q^2 = 400 \implies Q^* = 20\]At $Q = 20$: ATC = $\frac{200}{20} + 10 + 0.5(20) = 10 + 10 + 10 = $30$
| Q | FC | VC | TC | MC | ATC | AVC |
|---|---|---|---|---|---|---|
| 5 | 200 | 62.50 | 262.50 | 15 | 52.50 | 12.50 |
| 10 | 200 | 150 | 350 | 20 | 35.00 | 15.00 |
| 15 | 200 | 262.50 | 462.50 | 25 | 30.83 | 17.50 |
| 20 | 200 | 400 | 600 | 30 | 30.00 | 20.00 |
| 25 | 200 | 562.50 | 762.50 | 35 | 30.50 | 22.50 |
| 30 | 200 | 750 | 950 | 40 | 31.67 | 25.00 |
Confirms: MC crosses ATC at Q = 20, where ATC is minimized at $30.
3.5 Profit Margin (Average Profit)
\[\text{Average Profit} = \frac{\text{Profit}}{Q} = \frac{TR - TC}{Q} = P - ATC\]- If Price > ATC β firm earns positive profit
- If Price < ATC β firm incurs losses
- If Price = ATC β firm breaks even (zero economic profit)
3.6 Variety of Cost Patterns
Different industries have very different cost structures:
| Industry Type | Fixed Costs | Variable Costs | Example |
|---|---|---|---|
| High FC, Low VC | Very high | Low per unit | Website/software, pharmaceutical R&D |
| Low FC, High VC | Very low | Proportional to output | Lawn care, snow shoveling |
| Sharp diminishing returns | Moderate | Rise steeply at capacity | 24/7 manufacturing plant |
4. Production in the Long Run
4.1 All Inputs Are Variable
In the long run, a firm can adjust everything β capital, technology, plant size, location. The production function becomes:
\[Q = f(L, K)\]Because diminishing marginal product is caused by fixed capital, there are no diminishing returns in the long run β firms can scale all inputs together.
Typing Firm Example
Short run (K = 1 PC):
| Typists | 1 | 2 | 3 | 4 | 5 | 6 |
|---|---|---|---|---|---|---|
| Letters/hr | 5 | 7 | 8 | 8 | 8 | 8 |
| MP | 5 | 2 | 1 | 0 | 0 | 0 |
Diminishing returns hit hard after typist 1 β only one PC!
Long run (K = 3 PCs):
| Typists | 1 | 2 | 3 | 4 | 5 | 6 |
|---|---|---|---|---|---|---|
| Letters/hr | 5 | 10 | 15 | 17 | 18 | 18 |
| MP | 5 | 5 | 5 | 2 | 1 | 0 |
With more capital, the firm can hire 3 workers before diminishing returns set in. The long-run production function shows the most efficient way of producing any output level.
5. Costs in the Long Run
5.1 Choice of Production Technology
In the long run, firms choose among alternative production technologies β different combinations of labor and capital that produce the same output. The profit-maximizing firm picks the least-cost technology given current factor prices.
Park Cleaning Example β three methods to clean one park:
| Technology | Workers | Machines |
|---|---|---|
| Tech 1 (labor-intensive) | 10 | 2 |
| Tech 2 (balanced) | 7 | 4 |
| Tech 3 (capital-intensive) | 3 | 7 |
How the optimal choice shifts with wages:
| Scenario | Wage/Worker | Machine Cost | Tech 1 Cost | Tech 2 Cost | Tech 3 Cost | Best |
|---|---|---|---|---|---|---|
| A | $40 | $80 | $560 | $600 | $680 | Tech 1 |
| B | $55 | $80 | $710 | $705 | $725 | Tech 2 |
| C | $90 | $80 | $1,060 | $950 | $830 | Tech 3 |
As wages rise, firms substitute capital for labor β this explains why the demand curve for any input slopes downward.
5.2 Economies and Diseconomies of Scale
Economies of scale: As output increases, long-run average cost decreases. Bigger is cheaper per unit.
Constant returns to scale: Expanding output does not change average cost.
Diseconomies of scale: As output increases, long-run average cost increases. The firm has grown too large to manage efficiently.
| Region | LRAC Behavior | Cause | Example |
|---|---|---|---|
| Economies of scale | Falling β | Specialization, bulk purchasing, spreading fixed costs | Chemical plants (six-tenths rule), Amazon warehouses |
| Constant returns | Flat β | Efficient scale reached | Multiple identical plants |
| Diseconomies of scale | Rising β | Management complexity, communication failures | Overly large Soviet-era factories |
The Six-Tenths Rule (chemical engineering): Increasing output by a certain percentage raises total cost by only about six-tenths of that percentage. A pipe with twice the circumference (2Γ material cost) carries four times the volume β because area scales with the square of the radius.
5.3 Short-Run vs. Long-Run Average Cost Curves
The LRAC curve is the envelope (lower boundary) of all possible SRAC curves:
- Each SRAC curve corresponds to one level of fixed costs (one plant size)
- The LRAC curve traces the lowest-cost SRAC for every output level
- A firm planning for the long run picks the plant size (SRAC) that minimizes cost for its target output
Diagram β LRAC as Envelope of SRAC Curves:
Donβt confuse diminishing returns with diseconomies of scale!
- Diminishing marginal returns β short run, one input varies, capital fixed
- Diseconomies of scale β long run, ALL inputs increase together
An industry can have both diminishing marginal returns in the short run AND economies of scale in the long run. They describe different time horizons.
5.4 LRAC and Industry Structure
The shape of the LRAC curve determines the number and size of firms in an industry:
| LRAC Shape | Market Implication | Example |
|---|---|---|
| Sharp minimum at one point | All firms will be roughly the same size | Standardized manufacturing |
| Flat bottom over a range | Firms of varying sizes can compete | Many consumer goods industries |
| Minimum at output > market demand | Monopoly likely β only one firm can reach efficient scale | Local utilities, natural monopoly |
| Minimum at output βͺ market demand | Many competitors | Agriculture, restaurants |
Dishwasher Market:
- Market demand: 1 million units/year at $500
- If LRAC minimum is at 10,000 units β about 100 equal-sized firms
- If LRAC minimum is at 500,000 units β only 2 firms (oligopoly)
- If LRAC minimum is at 1.5 million units β likely a monopoly
5.5 Shifting Technology and LRAC
New production technologies can shift the LRAC curve, changing industry structure:
- Traditional trend (20th century): Assembly lines, large stores shifted LRAC right β favored larger firms
- Modern counter-trend: Small-scale natural gas turbines (100 MW vs. 300β600 MW), Pirelliβs robot tire factory (1M vs. 6M tires/year) β smaller firms can compete
- Digital economy: Winner-take-all (Amazon, Microsoft) vs. small firms reaching global markets β the outcome varies by industry
Case Study β Software vs. Manufacturing Cost Structures:
| Metric | Software (e.g., Microsoft Office) | Manufacturing (e.g., Toyota cars) |
|---|---|---|
| Fixed costs | Extremely high (R&D: billions) | High (factories, tooling) |
| Marginal cost | Near zero (copy a file) | Significant (steel, labor, parts) |
| ATC behavior | Falls continuously with more users | U-shaped, minimum at efficient scale |
| LRAC shape | Always declining β natural monopoly tendency | U-shaped β room for rivals |
| Industry structure | Few dominant firms (winner-take-most) | Many firms of varying sizes |
This explains why tech industries tend toward monopoly/oligopoly (Google Search, Windows, iOS/Android) while manufacturing supports more competition. The near-zero marginal cost of software means the first firm to reach scale has an almost unbeatable cost advantage.
Case Study β Tesla Gigafactory & Economies of Scale:
Teslaβs Gigafactory Nevada (opened 2016) demonstrates the power of economies of scale:
- Battery costs before Gigafactory: ~$200/kWh
- Target at full scale: ~$100/kWh (50% reduction)
- How? Vertical integration (raw materials β finished pack), 6,500+ workers under one roof, bulk purchasing, automated assembly
- Scale: Planned to produce more lithium-ion batteries annually than the entire world produced in 2013
The six-tenths rule applies: doubling factory floor area less than doubles construction cost, but can more than double output through better layout and automation.
6. Key Takeaways
-
Economic profit (not accounting profit) reveals true business viability β it accounts for the opportunity cost of all resources, including the ownerβs time and capital.
-
The production function $Q = f(L, K)$ links inputs to output. In the short run, $K$ is fixed, so only $L$ varies.
-
Diminishing marginal product is inevitable in the short run β with fixed capital, each additional worker contributes less.
-
Marginal cost is the hero metric for decision-making: compare MC to the price received for the next unit to decide whether producing it adds to profit.
-
MC intersects ATC at its minimum β below that intersection, ATC falls; above it, ATC rises.
-
Profit per unit = Price β ATC. If Price > ATC, the firm profits. If Price < ATC, losses.
-
In the long run, firms choose among production technologies, substituting cheaper inputs for expensive ones.
-
Economies of scale explain why some industries have a few large firms; diseconomies of scale explain why firms donβt grow infinitely.
-
The LRAC curve (envelope of SRAC curves) determines industry structure: its minimum relative to market demand predicts how many firms will compete.
7. Practice Questions
Q1. A firm has total revenue of $800,000. It pays $300,000 in wages, $100,000 in rent, and $50,000 in materials. The owner could earn $200,000 working elsewhere. What is the firmβs (a) accounting profit and (b) economic profit?
Answer: (a) Accounting profit = $800,000 β ($300,000 + $100,000 + $50,000) = $350,000 (b) Economic profit = $350,000 β $200,000 (implicit cost) = $150,000
Q2. Explain why a business can have positive accounting profit but negative economic profit. What does negative economic profit signal?
Answer: Accounting profit ignores implicit costs. If the ownerβs foregone salary, foregone rental income, or foregone returns on invested capital exceed the accounting profit, economic profit turns negative. This signals the owner would be better off using their resources elsewhere β the business is not the most valuable use of those resources.
Q3. Fill in the marginal product column:
| Workers | Total Product | Marginal Product |
|---|---|---|
| 0 | 0 | β |
| 1 | 8 | ? |
| 2 | 20 | ? |
| 3 | 28 | ? |
| 4 | 34 | ? |
| 5 | 38 | ? |
| 6 | 40 | ? |
At what point do diminishing marginal returns begin?
Answer: MP: 8, 12, 8, 6, 4, 2. Diminishing marginal returns begin after the 2nd worker (MP falls from 12 to 8).
Q4. A barbershop has fixed costs of $200/day. Each barber costs $100/day. With 3 barbers, the shop produces 45 haircuts. With 4 barbers, it produces 52. What is the marginal cost of the haircuts between 45 and 52?
Answer: ΞTC = $100 (one more barber). ΞQ = 7 haircuts. MC = $100 / 7 β $14.29 per haircut.
Q5. Why is the ATC curve typically U-shaped?
Answer: At low output, ATC is high because fixed costs are spread over very few units (high AFC). As output rises, AFC falls and ATC declines. Eventually, diminishing marginal returns cause VC to rise faster than output, pushing ATC back up. The combination of falling AFC and rising AVC creates the U-shape.
Q6. If MC is below ATC, what is happening to ATC? Why?
Answer: ATC is falling. If the cost of the marginal (next) unit is lower than the current average, it pulls the average down β just as a quiz score below your class average pulls your average down.
Q7. A firm sells its product at $15. Its ATC at current output is $12, and its AVC is $9. Is the firm profitable? What is its profit margin per unit?
Answer: Yes, Price ($15) > ATC ($12), so the firm is profitable. Profit margin = P β ATC = $15 β $12 = $3 per unit.
Q8. In the park cleaning example, if workers cost $70 each and machines cost $60 each, which of the three technologies should the firm use?
Answer:
- Tech 1: (10 Γ $70) + (2 Γ $60) = $700 + $120 = $820
- Tech 2: (7 Γ $70) + (4 Γ $60) = $490 + $240 = $730
- Tech 3: (3 Γ $70) + (7 Γ $60) = $210 + $420 = $630
Tech 3 is cheapest at $630. With relatively high wages, the firm substitutes toward capital-intensive production.
Q9. A typing firm currently has 1 PC and can produce 8 letters/hour with 3 typists. In the long run, it acquires 3 PCs and can produce 15 letters/hour with 3 typists. Explain why long-run production does not exhibit the same diminishing returns.
Answer: In the short run (1 PC), diminishing returns occur because additional typists share the same fixed capital. In the long run, the firm increases both labor and capital proportionally (3 typists + 3 PCs), so each worker has adequate equipment. Diminishing marginal product is caused by fixed capital β when capital adjusts, the constraint is removed.
Q10. Explain the difference between economies of scale and diminishing marginal returns. Can an industry experience both?
Answer: Diminishing marginal returns is a short-run phenomenon: with capital fixed, adding more labor eventually yields less extra output. Economies of scale is a long-run phenomenon: when all inputs grow together, average cost may fall. Yes, an industry commonly experiences both β diminishing returns in day-to-day operations (short run) and economies of scale when expanding plant capacity (long run).
Q11. The market for dishwashers demands 1,000,000 units per year at $500. If the LRAC has a flat bottom from 5,000 to 20,000 units, how many firms could exist in this market?
Answer: Between 1,000,000 / 20,000 = 50 firms and 1,000,000 / 5,000 = 200 firms. The flat bottom means firms of varying sizes (5kβ20k units) can coexist and compete effectively.
Q12. Why might a natural monopoly arise? Use the LRAC curve to explain.
Answer: A natural monopoly arises when the LRAC curveβs minimum occurs at an output level equal to or greater than total market demand. In this case, a single firm can serve the entire market at lower average cost than two or more firms could. Any potential competitor producing less output would have higher average costs and could not compete on price.
Q13. A firm invests its own cash (earning 4% in the bank) into a project that returns 6%. A friend suggests itβs a slam dunk since thereβs no interest to pay. Is the friend correct? What is the economic profit consideration?
Answer: The friend is wrong. The foregone 4% bank return is an implicit cost. The economic return is 6% β 4% = 2% β still positive, so the investment is worthwhile, but itβs not βfree money.β If the project returned only 3%, the economic profit would be negative (3% β 4% = β1%), and the firm would be better off keeping money in the bank.
Q14. Given $TC = 500 + 8Q + 0.2Q^2$, find (a) the MC function, (b) the ATC function, (c) the output where ATC is minimized, and (d) the minimum ATC value.
Answer: (a) $MC = \frac{dTC}{dQ} = 8 + 0.4Q$ (b) $ATC = \frac{500}{Q} + 8 + 0.2Q$ (c) Set MC = ATC: $8 + 0.4Q = \frac{500}{Q} + 8 + 0.2Q$ β $0.2Q = \frac{500}{Q}$ β $Q^2 = 2500$ β $Q^* = 50$ (d) $ATC(50) = \frac{500}{50} + 8 + 0.2(50) = 10 + 8 + 10 = $28$
Q15. A semiconductor fab costs $15 billion to build and can produce 50,000 wafers/month. A smaller fab costs $5 billion for 12,000 wafers/month. Compare the cost per wafer of capacity for each. What does this illustrate?
Answer: Large fab: $15B / 50,000 = $300,000 per wafer/month of capacity. Small fab: $5B / 12,000 = $416,667 per wafer/month of capacity. The large fab has 28% lower cost per unit of capacity β demonstrating economies of scale. This is why the semiconductor industry is dominated by a few massive manufacturers (TSMC, Samsung, Intel).
Q16. Software company A spends $50M on development and has marginal cost near $0. Company B makes furniture with $2M setup and $200/unit marginal cost. Draw/describe their ATC curves and predict industry structure.
Answer: Company A: $ATC = \frac{50,000,000}{Q} + 0$ β ATC falls continuously (always-declining curve). This creates a natural monopoly tendency; the first firm to reach scale has an enormous advantage. Industry: oligopoly/monopoly.
Company B: $ATC = \frac{2,000,000}{Q} + 200$ β ATC falls toward $200 but never below. Minimum efficient scale reached at moderate output. Industry: competitive market with many firms, since any firm producing moderate quantities has similar costs.