Module 9.4 Perfect Competition in Economic Profits

Overview of Perfect Competition
  • Definition: A market structure where numerous small firms compete against each other, selling identical products with no barriers to entry.
Conditions of Perfect Competition

  • Many Buyers and Sellers:

    • Firms are small relative to the market, meaning no single buyer or seller can affect market prices.

  • Identical Products:

    • All products are the same; consumers have no preference for one seller over another (e.g., agricultural products like berries).

  • No Barriers to Entry:

    • Anyone can enter or exit the market freely, which leads to a large number of competitors.
Price Takers
  • Price Taking Behavior: Firms in a perfectly competitive market are price takers, meaning they accept the market price determined by supply and demand.
  • Example: If a firm tries to charge more than the market price, it will sell nothing as consumers will switch to competitors offering the same product for less.
Market Dynamics
  • Determining Market Price:
    • Price is established through the interaction of supply and demand.
    • On a graph, the equilibrium price is set where the quantity supplied equals quantity demanded.
    • Example: Market price set at $4 for 100 million packs of berries.
Marginal Revenue in Perfect Competition
  • Marginal Revenue:
    • In a perfectly competitive market, marginal revenue is constant and equals market price (here, $4).
    • It is defined as the change in total revenue from selling one additional unit.
    • Thus, the demand curve faced by the firm is perfectly elastic.
Revenue Calculations
  • Total Revenue:
    • Calculated as the price per unit times the number of units sold.
    • Examples:
      • 10 units: $4 × 10 = $40
      • 20 units: $4 × 20 = $80
      • 200 units: $4 × 200 = $800
Profit Maximization
  • Profit Calculation:
    • Profit is revenue minus total cost.
    • Initial losses occur when total revenue doesn’t cover fixed costs.
    • Profit trajectory may look like:
      • Zero: -$62 (loss)
      • Max Profit between 70 and 80 units sold (possible positive profit)
Marginal Analysis for Profit Maximization
  • Rule of Thumb: Firms use marginal analysis to adjust production:
    • If MR > MC: Increase production; more units = higher profits.
    • If MR < MC: Decrease production; more units = losses.
    • Optimal production point occurs where MR=MCMR = MC.
Graphical Representation
  • Marginal Cost and Marginal Revenue:
    • The graph where the marginal revenue line (MR=4MR=4) intersects the marginal cost curve indicates the profit-maximizing quantity of output.
    • Key takeaway: In a perfectly competitive market, we have P=MR=MCP = MR = MC at equilibrium.