Market & Positioning

Total Addressable Market

Also known as: TAM, TAM / SAM / SOM

The total revenue opportunity for a product if it captured 100% of its market — usually paired with the narrower SAM (serviceable) and SOM (obtainable).

Definition

Total addressable market (TAM) is the entire revenue opportunity available for a product or service if it achieved complete market share — the size of the whole pie. It is almost always presented alongside two narrower figures: SAM (serviceable addressable market), the portion your business model and reach can actually serve, and SOM (serviceable obtainable market), the realistic slice you can win in a given horizon given competition and capacity.

The trio matters for prioritisation and fundraising: a large TAM signals headroom, while SAM and SOM force honesty about what is genuinely reachable. The common failure is a top-down TAM inflated by a vanity multiplication ("everyone in this industry × a price"), when the defensible number is built bottom-up from real segments and realistic penetration.

A credible market size accounts for competitors already holding share — your SOM is bounded by who else is fighting for the same buyers. Sizing an opportunity without mapping the incumbents overstates what is obtainable.

Why it matters for competitive intelligence

Your obtainable market is capped by the competitors already in it. A market-size estimate that ignores incumbents' share is the number that misleads a board and a roadmap.

How Rivalize helps

Rivalize helps ground the "obtainable" end of the estimate by mapping who already competes for the same buyers and how strong their presence is — sourced, not assumed.

Related terms

See it in practice on Rivalize

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Sources

  1. Standard market-sizing framework in strategy and venture finance.

This definition is an educational summary of an established concept, written by the Rivalize team. It is not affiliated with, or endorsed by, the originators of the framework.