Market Structures

Market structure refers to the organizational and other characteristics of a market. We focus on the number of firms, the nature of the product, and the ease of entry and exit. The JAMB syllabus divides this into Perfectly Competitive Markets and Imperfect Markets (Monopoly and Monopolistic Competition).

1. Perfectly Competitive Market

A perfectly competitive market is a theoretical market structure where competition is at its greatest possible level. To be classified as such, it must meet these assumptions:

• Many Buyers and Sellers: No single participant has the power to influence the market price.
• Homogeneous Products: Goods are identical (e.g., primary agricultural products).
• Free Entry and Exit: Firms can enter or leave the industry without legal or financial barriers.
• Perfect Knowledge: Buyers and sellers have full information about prices and product quality.
• Price Taker: The firm accepts the price determined by market forces (Demand and Supply). The AR and MR curves are horizontal and equal to Price.

Short-run and Long-run Equilibrium

• Short-run: A firm can make supernormal profit (AR > AC), normal profit (AR = AC), or a loss (AR < AC). The firm produces where MC = MR and MC is rising.
• Long-run: Due to free entry/exit, supernormal profits attract new firms, increasing supply and lowering price. Conversely, losses cause firms to leave. Thus, in the long run, firms only earn Normal Profit (P = MC = AC).

2. Imperfect Markets

A. Pure Monopoly

A market with a single seller of a product with no close substitutes. Characteristics include:

• One seller, many buyers.
• High barriers to entry (Legal, technical, or financial).
• The firm is a Price Maker.
• Downward-sloping demand curve (AR and MR are separate; MR < AR).

B. Discriminatory Monopoly

This occurs when a monopolist charges different prices to different consumers for the same product, for reasons not associated with cost differences. Conditions include market segmentation and different price elasticities of demand.

C. Monopolistic Competition

A hybrid between monopoly and perfect competition. Features include:

• Many sellers and buyers.
• Product Differentiation: Goods are similar but not identical (branding, packaging).
• Relatively easy entry and exit.
• Some control over price (Brand loyalty).

Equilibrium in Imperfect Markets

• Short-run: Monopolies and monopolistic competitors can earn supernormal profits where MC = MR.
• Long-run (Monopoly): Can maintain supernormal profits due to barriers to entry.
• Long-run (Monopolistic Competition): New firms enter due to low barriers, shifting the individual firm's demand curve to the left until only Normal Profit is made.

3. Break-even and Shut-down Analysis

• Break-even Point: This is the point where Total Revenue (TR) equals Total Cost (TC), or Price (P) equals Average Total Cost (ATC). The firm makes normal profit.
• Shut-down Point: In the short run, a firm will continue to produce as long as it can cover its Average Variable Cost (AVC). If the Price (P) falls below the minimum AVC, the firm should shut down to minimize losses.