Why do some firms grow large while others stay small, and how do they expand?
The reasons firms grow or stay small, organic and inorganic growth, types of integration, the principal-agent problem and the divorce of ownership from control.
An Edexcel A-Level Economics A answer to business growth, covering why firms grow or remain small, organic versus inorganic growth, horizontal, vertical and conglomerate integration, demergers, and the principal-agent problem arising from the divorce of ownership and control.
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What this dot point is asking
Edexcel wants you to explain why firms grow or stay small, distinguish organic from inorganic growth, classify the types of integration, and explain the principal-agent problem caused by the divorce of ownership from control.
Why firms grow or stay small
The divorce of ownership from control and the desire for a quiet life can also keep firms small, while some small firms supply a niche the giants ignore.
Organic and inorganic growth
Types of integration
- Horizontal integration: firms at the same stage of the same industry combine (two supermarkets), raising market share and economies of scale but also monopoly power.
- Vertical integration: firms at different stages combine. Forward integration is toward the customer (a brewer buying pubs); backward integration is toward the supplier (a brewer buying a hop farm). It secures supply or distribution and can raise barriers to entry.
- Conglomerate integration: firms in unrelated industries combine, spreading risk through diversification but risking a lack of synergy and management focus.
A demerger is the opposite: a firm splits into separate businesses, often to cut diseconomies of scale, focus on core activities or raise the combined market value.
The principal-agent problem
Firms try to align incentives through performance-related pay, share options and oversight by non-executive directors.
Examples in context
- Sainsbury's and Asda (2019). The CMA blocked this horizontal merger, fearing higher prices and less choice, a textbook competition-policy case.
- Amazon's vertical integration. Amazon's move into logistics and cloud (AWS) shows backward and forward integration securing the value chain.
- Unilever. A conglomerate spanning food, home and personal care, illustrating diversification to spread risk.
- eBay and PayPal demerger (2015). A demerger to let each business focus and raise combined shareholder value.
Try this
Q1. Distinguish between forward and backward vertical integration. [3 marks]
- Cue. Forward is integration toward the customer (buying a distributor); backward is toward the supplier (buying a supplier).
Q2. Explain the principal-agent problem in a public limited company. [4 marks]
- Cue. Owners (shareholders) and managers differ, so managers may pursue their own goals (salary, growth) rather than maximising shareholder profit.
Exam-style practice questions
Practice questions written in the style of Pearson Edexcel exam questions on this dot point, with worked answer explainers. The year tag is the paper they imitate, not the source.
Edexcel 20194 marksA firm's average cost falls from to per unit when output doubles after a horizontal merger. Calculate the percentage fall in unit cost and identify the source of the saving.Show worked answer →
A short calculate question on economies of scale from integration.
Percentage fall .
The saving comes from economies of scale realised through horizontal integration: spreading fixed costs over more output and gaining purchasing, technical and managerial economies.
Markers reward (1) the percentage-change method, (2) , (3) linking the fall to economies of scale from combining firms at the same stage.
Edexcel 202212 marksAssess the likely effects of horizontal integration between two large firms on consumers in the affected market.Show worked answer →
A 12 mark question (around 8 KAA, 4 evaluation).
KAA: explain that horizontal integration raises market share and economies of scale, which can lower average costs and prices, but also raises monopoly power, which can raise prices, cut choice and reduce allocative efficiency, with a diagram of falling LRAC versus rising market power.
Evaluation: the net effect on consumers depends on whether cost savings are passed on, the contestability of the market, regulatory scrutiny by the CMA, and dynamic efficiency gains from greater R&D. Reach a justified judgement.
Markers reward applied analysis and balanced evaluation.
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Sources & how we know this
- Pearson Edexcel A-Level Economics A (9EC0) specification — Pearson Edexcel (2015)