Monopoly & Antitrust — Comprehensive Bullet-Point Notes

15.1 Is Any Firm Ever Really a Monopoly?

• Definition
  • Monopoly = single seller of a good/service without a close substitute.
• Why study it?
  • Some real-world firms are (near) monopolists → need to understand their behavior.
  • Helps detect collusion/ cartel behavior; colluding firms mimic a monopoly.
• Market-definition subtlety (small-town pizzeria example)
  • If customers treat other fast foods / frozen pizzas as close substitutes → not a monopoly.
  • If consumers view pizzeria’s product as unique → monopoly.
  • Either way, firm enjoys market power → ability to raise $P$ above $MC$ and earn economic profit.
• USPS “monopoly in your mailbox”
  • 1792: Congress made private mail delivery illegal.
  • 1934: Only postal employees allowed to put items in residential mailboxes.
  • Competition (FedEx, UPS, internet) ↓ mail volume ≈ 45 % since 2000.
  • 2020 delivery issues rekindled debate; USPS lost $\$2.7\text{ billion}$ in 2021.
  • Justification = universal service obligation (cross-subsidize rural delivery).

15.2 Where Do Monopolies Come From?

Monopoly requires barriers to entry. Four main sources:

1. Government restrictions on entry
   • a) Patents, copyrights, trademarks
     • Patent = 20-yr exclusive right (e.g., pharmaceuticals).
     • Copyright = exclusive right for creative works (books, films).
     • Trademark = protected brand names/symbols; never expire (Hasbro owns “Monopoly” board-game name; sued creator of Anti-Monopoly, later licensed).
     • Rationale: let firms recoup high fixed R&D costs → encourages innovation.
   • b) Public franchise / public enterprise
     • Gov’t designates sole legal provider (water, electricity, USPS).
     • In Europe more common for gov’t to operate the firm.
2. Control of a key resource
   • Alcoa once controlled almost all bauxite → strong barrier.
   • NFL contracts top players → blocks rival leagues.
3. Network externalities
   • Product value ↑ with number of users (eBay, Windows, Facebook).
   • Creates virtuous cycle for incumbent; may lock-in consumers to inferior tech.
4. Natural monopoly
   • Economies of scale so large that one firm supplies entire market at lower $ATC$ than 2+ firms.
   • Typical when fixed costs high, $MC$ low (electric utilities).
   • Graphical insight (Fig 15.1): single-firm $ATC$ at A < two-firm $ATC$ at B.

15.3 How Does a Monopoly Choose Price & Output?

• No rivals ⇒ no strategic interaction; monopoly maximizes profit like any single firm: choose $Q$ where $MR = MC$.
• Faces downward-sloping demand ⇒ to sell more, must cut price.
  • Results in MR < P (extra revenue minus price drop on previous units).
• USPS stamp example (Fig 15.2)
  • Table for 0–10 customers shows $P$, $TR$, $AR$, $MR$.
  • $MR$ declines faster than price; once MR<MC, stop selling.
• Profit computation
  • Choose $Q_M$ where $MC=MR$.
  • Charge $P<em>M$ from demand curve directly above $Q</em>M$.
  • Profit = $(P<em>M-ATC)\times Q</em>M$.
• Long run
  • Entry blocked ⇒ short-run = long-run; monopoly profits persist.
• Low-demand monopoly stories
  • Columbus Washboard Co. sole washboard maker (≈ 11 000 units/yr) but profits minimal.
  • Slide-rule start-up would still fail; monopoly power useless if demand ≈ 0.

15.4 Does Monopoly Reduce Economic Efficiency?

• Thought experiment: competitive athletic-shoe market becomes monopoly.
  • Competitive equilibrium $P<em>C, Q</em>C$ maximizes economic surplus.
  • Monopoly sets $MR=MC$ ⇒ $Q<em>M<Q</em>C$, $P<em>M>P</em>C$.
• Welfare changes (Fig 15.5)
  • Consumer surplus ↓ by areas $A+B$.
  • Producer surplus: gains $A$, loses $C$ (shaded differently) ⇒ net producer gain.
  • Deadweight loss = areas $B+C$ (lost trades where WTP>MC but not executed).
• Aggregate magnitude
  • Pure monopolies rare, but market power common (any non-perfect-competition firm).
  • Estimated U.S. DWL from market power < 1 % of GDP (≈ $\$786$/person).
• Market power & innovation
  • Joseph Schumpeter’s “gale of creative destruction”: future monopoly profits motivate R&D; long-run consumer gains may outweigh short-run higher prices.

15.5 Price Discrimination

• Definition: charging different prices to different buyers for same product without cost differences.
• Everyday examples: student/senior movie discounts, airline fares.
• Legal dimension
  • Discrimination by race/gender illegal; by willingness to pay usually legal.
  • Car insurers charge men > women due to accident data; race-based pricing would violate civil-rights laws.
• Feasibility conditions
  1. Market power (firm not price-taker).
  2. Identifiable demand differences across groups.
  3. No profitable arbitrage (resale impractical).
• Movie theater graph (Fig 15.6)
  • Afternoon demand lower ⇒ $P_{PM} = \$8.50$; evening demand higher ⇒ higher optimal $P$.
• Airlines (Table 15.1)
  • Detect business vs leisure via booking timing/stay length; fall 2023 example NY–SF: $\$528$ (biz) vs $\$222$ (leisure).
• Big Data & dynamic pricing
  • Continual price updates = “yield management”.
  • Disney MagicBand, AMC seat pricing (+$1$ preferred, –$2$ value), auto-insurance premium elasticity.
• Perfect (first-degree) price discrimination
  • Charge each consumer exactly their $WTP$.
  • CS = 0, firm captures entire surplus, but efficient quantity produced (D intersects MC) ⇒ DWL = 0.
  • In reality, perfect info unobtainable, but concept shows PD can reduce inefficiency.
• Ambiguous welfare outcome
  • PD ↑ firm profit, ↓ consumer surplus, total effect on DWL unclear (depends on whether output expands).
• Intertemporal PD
  • Hard-cover vs paperback; early adopters have higher WTP, pay more.
• Robinson-Patman Act (1936)
  • Outlawed PD that lessens competition; broad wording but courts generally permit PD if competition ↑. 1960s Borden milk case: store-brand discount allowed.

15.6 Government Policy Toward Monopoly

• Governments respond because monopoly ↓ CS & efficiency.
• Two main tools
  1. Antitrust laws against collusion & anti-competitive mergers.
  2. Regulation of natural monopolies.

Major Antitrust Statutes (Table 15.2)

• Sherman Act 1890: banned “restraint of trade,” price fixing, monopolization.
• Clayton Act 1914: prohibited stock purchases/ interlocking directorates among competitors.
• Federal Trade Commission Act 1914: created FTC.
• Robinson–Patman Act 1936: forbade PD that lessens competition.
• Celler–Kefauver Act 1950: strengthened merger restrictions.

Merger Policy

• Distinguish
  • Horizontal merger (same industry) → market power ↑.
  • Vertical merger (different stages) → less scrutiny.
• DOJ & FTC Guidelines
  1. Market definition: smallest set of products where hypothetical price rise raises total profits (no escape via substitutes).
  2. Concentration measure: Herfindahl–Hirschman Index $HHI = \sum s<em>i^2$ where $s</em>i$ = % market share.
  • Examples:
    • Single firm: $HHI = (100)^2 = 10{,}000$.
    • Two equal firms 50/50: $HHI = 50^2+50^2 = 5{,}000$.
    • Ten firms @10 % each: $HHI =10\times10^2 = 1{,}000$.
  1. Standards (Table 15.3)
  • Post-merger HHI<1500 → markets “unconcentrated”, mergers allowed.
  • $1500\le HHI \le 2500$ → moderately concentrated; ∆$HHI$>100 may be challenged.
  • HHI>2500 (highly concentrated); ∆$HHI$>200 likely challenged.
• Biden administration debate: should protection extend beyond consumers to small business competitors?

Regulation of Natural Monopolies

• Unregulated monopoly chooses $P<em>M, Q</em>M$ where $MR=MC$ → DWL.
• Efficient point $MC = D$ yields $P<em>E$ but firm would incur loss (because PE<ATC).
• Regulatory compromise (Fig 15.8)
  • Set regulated price $P_R$ where firm earns zero economic profit (price intersects $ATC$).
  • Output $Q<em>R$ ≥ $Q</em>M$, DWL shrinks compared with no regulation.

Connections & Implications

• Market structures studied across course: Perfect Competition → Monopolistic Competition → Oligopoly → Monopoly (minimum competition benchmark).
• Collusion in oligopoly imitates monopoly; antitrust enforcement relies on understanding monopoly pricing logic.
• Ethical & policy trade-offs
  • Balancing innovation incentives (patents, market power) vs consumer prices.
  • Dynamic pricing raises privacy questions (firms exploit personal “big data”).
  • Antitrust’s scope: consumer welfare standard vs broader social goals (worker wages, small-firm survival).
• Quantitative highlights & formulas
  • Marginal revenue: $MR = \frac{\Delta TR}{\Delta Q}$.
  • Profit: $\pi = (P-ATC)\times Q$.
  • Deadweight loss under monopoly = areas where WTP > MC but sales foregone.
  • Herfindahl–Hirschman Index: $HHI = \sum<em>{i=1}^n s</em>i^{2}$ (% shares in whole numbers).

Key Takeaways for Exam Preparation

• Identify the four barriers to entry & provide real-world examples.
• Draw monopoly diagrams: demand, MR, MC, ATC, showing profit rectangle & DWL.
• Compare competitive vs monopoly outcomes for price, quantity, surplus.
• Explain the three prerequisites for price discrimination & give everyday cases.
• Calculate HHI and apply DOJ/FTC thresholds.
• Discuss regulatory pricing for natural monopoly and why $P=MC$ is infeasible.
• Evaluate pros/cons of monopoly power in fostering innovation (Schumpeter) vs harming efficiency.