Page 79 · Module 03, Know Your Market · this screen continues that page
All 108 frameworksTAM SAM SOM
Show investors and yourself - exactly how big this can get
The prompt
Copy & paste readyLabelsReplace theseSwap the role below
Pro tip, from the book
Investors are sceptical of top-down market sizing because anyone can find a large number. The founders who impress are those who say 'bottom-up, we see 12,000 companies that fit our ICP, average deal size is X, that gives us a Y SOM with Z% penetration in year 3.' That level of specificity signals you actually know your market.
Who should run this prompt
Module role profileWho should read your competitive landscape? Every market looks different depending on where you are standing. A market researcher sees data. A competitor's strategist sees opportunity. A customer sees none of your positioning — only their own problem. Use this page to choose the right lens before drawing any conclusions about the market you operate in.
Choose any role to drop it into the prompt above. Only the highlighted opening clause changes — the rest of the prompt stays exactly as printed.
◆◆◆◆◆ → ◆ seniority, board level down to specialist◈ outside the organisation
How to make any role sharper
- Add years of experience: "...with 15 years in enterprise SaaS" produces different depth than just the title.
- Add what they care most about: "You care most about [X]" shapes every word of the output.
- Add their communication style: "Be direct. Flag risks first. No jargon." changes the tone entirely.
Use this when
The problem it solvesAn investor asks how big your market is and you either say a very large number from a generic report or you have no credible answer. You need a market sizing methodology that is defensible and specific to your actual business.
How the framework works
From the printed pageTAM SAM SOM is the standard market sizing framework used by investors and strategists. Total Addressable Market (TAM) is the total global revenue opportunity if you captured 100% of the market. Serviceable Addressable Market (SAM) is the portion you can realistically reach with your current model. Serviceable Obtainable Market (SOM) is the realistic share you can capture in the next 3–5 years. The most common mistake is starting with TAM and working down. The best founders build bottom-up from real unit economics and work up.
The method, in four moves
Do these in orderBuild your SOM first from bottom-up: number of target accounts × average contract value.
Work up to SAM by expanding the customer definition while keeping your delivery model.
Use TAM to show the theoretical ceiling, but never lead with it.
Always show both top-down and bottom-up calculations, the difference reveals your assumptions. A TAM number from a generic market report will kill your credibility with an experienced investor faster than having no number at all. Build bottom-up from real unit economics, always.
Where the framework comes from
Venture capital due diligence methodology — TAM SAM SOM widely used 1990s onwards
Pairs well with
As printed with this frameworkModule 03 — Know Your Market
See your competitive landscape clearly before you move.
10 frameworks, printed on pages 70–89.
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