TAM, SAM, SOM
Total Addressable Market (TAM), Serviceable Addressable Market (SAM) and Serviceable Obtainable Market (SOM) are all measures of market size.
Example
Let’s say we’re evaluating the market for a company that sells roses:
TAM: The global market for all types of flowers = $500
SAM: The market for roses in the market that the company operates in = $300
SOM: The company’s expected sales based on its marketing, production and competitive positioning = $100
For a visualization, you’ll get something like this:
That’s all there is to it! Normally TAM and SAM are focused on the most when evaluating the future growth potential of a business.
In the room
Market sizing shows up in interviews and in every pitch deck you'll build as an analyst. The instinct that impresses is skepticism — TAM is routinely inflated, and noticing that signals commercial judgment.