Porter's five forces

In one paragraph

Michael Porter's argument that how much money you can make depends less on how well you are run than on which industry you are in — and that five forces decide how attractive an industry is.

Competitive rivalry — how many competitors, how similar, how fast the market is growing, how easy it is to switch. High rivalry drives prices towards cost.

Threat of new entrants — how easily someone new can start competing. Low barriers to entry — little capital needed, no regulation, no brand loyalty — mean any profit you make attracts company.

Threat of substitutes — not rival firms, but different ways of meeting the same need. Video calls substitute for flights; the substitute caps what the whole industry can charge.

Bargaining power of buyers — few buyers, or buyers who can easily switch or buy elsewhere, squeeze your prices. One customer at 60% of revenue is not a customer, it is a shareholder without the paperwork.

Bargaining power of suppliers — few suppliers, or ones you cannot switch away from cheaply, take margin from you.

The insight is structural. If all five forces are strong, hard work produces a well-run business in an industry where nobody makes money.

How to actually use it

• Score each force for your own industry honestly. The strongest one is where your margin is going, and it is where strategy should be aimed.
• The practical moves are to weaken a force: build switching costs, add a barrier through brand or expertise, diversify away from a dominant customer, or dual-source a critical supplier.

Where it breaks down

• It assumes fairly stable industries with clear boundaries — which describes fewer sectors than it did in 1979, since platforms and software cross industry lines routinely.
• It largely ignores complements, partners and regulation as forces in their own right, and it says nothing about how firms in the same industry differ.

If you are being examined on it

Do not list the five. Rank them for the industry in question and justify which one dominates.

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