Size Your Market Without Making Up a TAM

    You are a market analyst. Build a market size for this that survives someone checking it.

What I sell: {{product}}
Who buys it: {{customer_type}}
What they pay: {{price_and_frequency}}
Where I sell: {{geography}}
Any data I have: {{customer_counts_industry_reports_or_nothing}}

Start with the rule: never present a market size derived by taking a large industry figure and applying a percentage. "The global logistics market is $10 trillion and we only need 1%" is the single most reliable signal to an investor that a founder has not done the work. It shows nothing about whether anyone will buy, and 1% of a large number is not a plan.

Part 1 — Build bottom-up instead. Count and multiply:
- How many organisations or people fit the buyer definition, precisely stated? Name the source for the count — a census, an industry register, a company database, a professional body. If there is no source, say so and estimate transparently with the method shown.
- What share of those are realistically reachable given language, regulation, size, segment, and channel?
- What do they pay you per year, at your actual price, not an aspirational one?
- Multiply. That is your addressable market, and it is a number you can defend line by line.

Part 2 — Then give the three layers honestly:
- TAM: everyone who could conceivably buy this category
- SAM: those you can actually serve today with this product, in these geographies, at this price
- SOM: what you could plausibly win in three to five years, derived from your actual sales capacity and win rate — not a percentage of SAM

Part 3 — Sanity-check against reality:
- What is the largest company in this space doing in revenue? If the incumbent leader does $200M and you have sized the market at $50B, one of those is wrong, and it is not the incumbent.
- Cross-check with a top-down number from a published source. When bottom-up and top-down disagree by more than a factor of two or three, explain which you trust and why. Investors respect the reasoning more than the number.
- Is this a market that exists, or one that has to be created? Say which. A created market is not disqualifying, but pretending it already exists is.

Part 4 — Tell me the growth story: is this market growing, and because of what specific mechanism? "Digital transformation" is not a mechanism. A regulation with a compliance date is.

Then give me the two sentences I would actually say on a call, and the follow-up question a sceptical investor will ask about the weakest number in the chain.