In-Depth Notes on Competitive Markets

Competitive Markets

  • Market Structure: Refers to characteristics affecting firm behavior and performance.
    • Features: Number and size of sellers, knowledge of actions, freedom of entry, product differentiation.
    • Market Power: Firms can influence product pricing.

Theory of Perfect Competition

  • Assumptions:
    1. Homogeneous Product: All firms sell identical products.
    2. Known Characteristics and Prices: Consumers are aware of prices and product quality.
    3. Small Firms: No single firm can control market prices.
    4. Free Entry and Exit: No barriers to enter or leave the market.
  • Price Takers: Firms accept the market price instead of setting it.

Revenue Concepts

  • Total Revenue (TR): Total income from sales.
  • Average Revenue (AR): Revenue received per unit sold, equals TR divided by quantity sold.
  • Marginal Revenue (MR): Additional revenue from selling one more unit; important for decision-making in production.

Short-Run Decisions

  • Profit Maximization: Firms aim to maximize profits defined as:
    Profits=TR−TCProfits = TR - TC
  • Production Decisions:
    • If producing nothing, the firm incurs losses equal to fixed costs.
    • Shut-Down Price: Price at which the firm is indifferent to producing or shutting down; equal to the minimum of average variable costs (AVC).

Production Quantity Decision

  • Production Criteria:
    • Produce additional units if the marginal revenue (MR) exceeds marginal cost (MC).
    • The firm continues producing until MR=MCMR = MC.

Short-Run Supply Curves

  • The supply curve is derived from the marginal cost curve above the AVC.
  • As price and output levels change, the firm's decisions on production quantities vary accordingly.

Short-Run Equilibrium in a Competitive Market

  • Market Equilibrium: Occurs where the market supply and demand intersect.
  • Profit Outcomes:
    • Positive Profit: Price is above the average total cost (ATC).
    • Zero Profit: Price equals ATC (break-even point).
    • Losses: Price below ATC indicates the firm is incurring losses.

Long-Run Decisions

  • Entry and Exit in Market:
    1. Positive profits attract new firms, increasing supply and lowering price.
    2. Entry ceases when profits are zero (just covering total costs).
  • Exit Decisions: Firms exit if they incur continuous losses; this decreases market supply, hence increasing price.

Long-Run Equilibrium Conditions

  1. Firms must maximize profits at existing capital levels.
  2. No firm should suffer losses or earn profits long-term.
  3. No ability to increase profits by changing production size; must operate at minimum point of long-run average cost (LRAC) curve.

Changes in Technology

  • Technological advancements can lower costs for new plants.
  • Economic Profits: New technology can lead to profits for firms with improved productivity.
  • As more firms enter, the increased supply diminishes prices, aligning with costs of new plants, while older plants may exit due to losses.