Explain the differences between private‑sector and public‑sector firms, describe the main types of firms, compare small and large firms, outline mergers, economies and diseconomies of scale, define the key cost and revenue concepts, list the objectives that firms may pursue, and compare the two main market structures (perfect competition and monopoly).
Key Definitions
Firm: An organisation that combines factors of production to produce goods or services for sale.
Private‑sector firm: Owned by individuals, families, partnerships or shareholders; operates primarily for profit.
Public‑sector firm (state‑owned enterprise): Owned and controlled by the government; may pursue profit, but also social, political or policy objectives.
Primary, secondary and tertiary firms:
Primary: Extracts natural resources (e.g., a coal mine, a fishing fleet).
Secondary: Manufactures or processes raw materials into finished goods (e.g., a car factory, a textile mill).
Tertiary: Provides services rather than tangible goods (e.g., a bank, a supermarket, a hospital).
Classification of Firms
Sector
Ownership
Typical Objective(s)
Examples
Private‑sector (primary, secondary, tertiary)
Individuals, families, shareholders, partnerships
Profit maximisation (often also growth or survival)
Tesco (retail), BP (energy), Samsung (electronics)
Public‑sector (state‑owned)
Central, regional or local government
Social welfare, universal service provision, employment, price stability
BBC, NHS, Kenya Power
Characteristics of Private‑Sector Firms
Ownership is private – individuals, families, shareholders.
Primary objective is profit maximisation (often complemented by growth or survival).
Financed through:
Owner’s capital (equity)
Bank loans (debt)
Shares issued on stock markets
Decision‑making driven by market signals (price, cost, demand).
Subject to competition; free entry and exit.
Characteristics of Public‑Sector Firms
Owned and controlled by the government (central, regional or local).
Objectives may include:
Provision of essential services
Employment creation
Price stability for consumers
Social welfare and equity
Financed through:
Tax revenue
Government borrowing
Subsidies and grants
Decision‑making influenced by political considerations and policy goals.
Often protected from direct competition (monopolies or heavily regulated markets).
Small vs. Large Firms (Advantages & Disadvantages)
Aspect
Small Firm
Large Firm
Flexibility
High – can adapt quickly to market changes.
Lower – bureaucratic procedures slow response.
Access to finance
Limited – rely on owner’s capital or small loans.
Broad – can issue shares, obtain large bank loans.
Economies of scale
Few – higher average costs.
Many – lower average costs, bulk buying.
Market power
Very little – price taker.
Potentially significant – can influence price (especially in monopoly/oligopoly).
Management
Owner‑managed – close control.
Complex hierarchy – risk of coordination problems (diseconomies of scale).
Types of Mergers
Mergers combine two or more firms to form a larger entity. The three main types are:
Horizontal merger: Between firms that produce the same (or very similar) products and operate at the same stage of production. Example: British Airways merging with Iberia.
Vertical merger: Between firms at different stages of the production chain (e.g., a manufacturer and its supplier). Example: A car maker acquiring a tyre manufacturer.
Conglomerate merger: Between firms that have no common production processes or markets. Example: A food company acquiring a telecommunications firm.
Economies and Diseconomies of Scale
Economies of scale: Average total cost (ATC) falls as output increases because fixed costs are spread over more units and/or technical efficiencies are achieved.
Internal economies – larger plant, specialised labour, bulk buying, better use of machinery.
External economies – industry‑wide improvements such as better infrastructure, skilled local labour pool.
Diseconomies of scale: ATC rises when output continues to increase, often due to management difficulties, worker demotivation, or coordination problems.
Suggested diagram: ATC curve showing a downward‑sloping section (economies of scale) followed by an upward‑sloping section (diseconomies of scale).
Cost and Revenue Concepts
Concept
Definition
Formula (where applicable)
Total Revenue (TR)
Money received from sales of output.
TR = P × Q
Average Revenue (AR)
Revenue per unit of output.
AR = TR / Q = P
Total Cost (TC)
All costs incurred in producing a given level of output.
TC = FC + VC
Fixed Cost (FC)
Costs that do not vary with output (e.g., rent, salaries of permanent staff).
–
Variable Cost (VC)
Costs that vary directly with output (e.g., raw materials, hourly wages).
–
Average Total Cost (ATC)
Cost per unit of output.
ATC = TC / Q
Average Fixed Cost (AFC)
Fixed cost per unit of output.
AFC = FC / Q
Average Variable Cost (AVC)
Variable cost per unit of output.
AVC = VC / Q
Marginal Cost (MC)
Extra cost of producing one more unit.
ΔTC / ΔQ
Marginal Revenue (MR)
Extra revenue from selling one more unit.
ΔTR / ΔQ
Typical Firm Objectives (Cambridge Requirement)
Survival – staying in business.
Profit maximisation – highest possible profit.
Growth – increasing size, market share or output.
Social welfare – providing services at affordable prices (more common for public‑sector firms).
Decision‑Making in Private‑Sector Firms
Private firms aim to maximise profit (π):
$$\pi = TR - TC$$
Profit is maximised where marginal revenue equals marginal cost:
$$MR = MC$$
Key steps in the decision‑making process:
Estimate market demand and price elasticity.
Calculate expected total revenue: $TR = P \times Q$.
Identify the cost structure (fixed vs variable) and compute MC.
Adjust output until $MR = MC$.
Take account of any additional costs (taxes, interest) and decide on the final output level.
Decision‑Making in Public‑Sector Firms
Public firms balance several objectives, often expressed as a weighted function:
Private‑sector firms are owned by individuals or shareholders, aim primarily at profit maximisation, raise finance from private sources and respond directly to market forces. Public‑sector firms are owned by the government, pursue a range of social and economic objectives, are funded through taxation and borrowing, and their decisions are shaped by policy rather than pure market signals. Small firms are flexible but lack economies of scale; large firms enjoy lower average costs but may suffer coordination problems. Understanding these motivations, constraints, and typical market environments is essential for analysing how markets operate and the role of government in the economy.