Strategy

Porter's Five Forces

Five structural forces determine how much profit an industry can sustain — regardless of how clever the players are.

TL;DR

Industry structure, not management quality, explains most of long-run profitability.
The five forces: rivalry, new entrants, substitutes, supplier power, buyer power.
Score each force and identify the dominant one or two — that's where your strategy has to win or escape.
Pair with 7 Powers: Five Forces tells you about the industry, 7 Powers tells you about the firm.

What it is

Michael Porter published Five Forces in 1979 to answer a question every CEO and investor wrestles with: why are some industries permanently profitable while others bleed?

Airlines, restaurants, and retail are famously brutal. Software, pharma, and luxury are famously generous. Porter’s insight: the difference isn’t the smartness of the operators. It’s the structure of the industry. Five forces compress or expand the profit pool, regardless of who’s playing.

The five forces

1. Rivalry among existing competitors. How aggressively do players compete on price, marketing, and capacity? High when products are undifferentiated, fixed costs are high, exit is hard, or growth is slow.

2. Threat of new entrants. How easy is it for someone new to set up shop? Low when scale, capital, regulation, brand, or distribution form real barriers.

3. Threat of substitutes. Are there alternatives outside the industry that meet the same need? Train vs. plane. Video calls vs. business travel. Substitutes cap how much you can charge before customers leave the category entirely.

4. Bargaining power of suppliers. How much can your inputs squeeze you? High when there are few suppliers, switching is costly, or you’re a small share of their business.

5. Bargaining power of buyers. How much can your customers squeeze you? High when they’re concentrated, informed, price-sensitive, or buying a commoditized product.

How to apply it

Pick the industry, narrowly. “Software” is too broad — “enterprise CRM” is workable.
Score each force as Low / Medium / High and write one sentence on why.
Identify the dominant force. Usually one or two carry most of the weight.
Ask: is anything about to change? New entrant, new substitute, new regulation, consolidation on either side. The forces aren’t static.
Decide where to play, or how to reshape your position relative to the dominant force.

Industry structure explains more of long-run profitability than any individual company's choices.

A worked example: airlines vs. enterprise software

Airlines. Rivalry: brutal (price-transparent, low differentiation). Entrants: relatively easy at low end. Substitutes: trains, video calls. Suppliers: Boeing + Airbus duopoly, oil cartels, unionized labor — all powerful. Buyers: comparison sites mean almost zero switching cost. Five out of five forces are hostile. Industry margins reflect it.

Enterprise SaaS. Rivalry: moderate, often segmented by vertical. Entrants: capital and trust barriers are real. Substitutes: build-vs-buy, but rarely beats SaaS at scale. Suppliers: AWS/Azure are powerful but commoditized. Buyers: high switching costs once integrated. Two or three forces are favorable. Margins reflect that too.

Common pitfalls

Drawing the industry boundary too wide. “Retail” tells you nothing. “Off-price apparel in the US” tells you something.

Treating it as static. Forces shift. Streaming changed the music industry’s buyer power overnight. Generative AI is reshaping supplier dynamics in publishing right now.

Skipping the “why.” Scoring forces without explaining the mechanism produces a useless chart. The diagnosis matters more than the diagram.

When NOT to use it

Five Forces is an industry tool, not a company tool. It tells you whether the pond has fish. It doesn’t tell you whether your particular boat will catch them. Pair it with 7 Powers (firm-level) for the full picture.