SOM

What It Is

SOM (Serviceable Obtainable Market) is the portion of your Serviceable Available Market (SAM) that you can realistically win in a defined time frame, given your actual resources, distribution, brand, and competitive position. It is the most conservative and most operational figure in the classic market sizing trio:

• TAM (Total Addressable Market): total demand if you had 100% market share.
• SAM (Serviceable Available Market): the slice of TAM your product, geography, and business model can actually serve.
• SOM (Serviceable Obtainable Market): the slice of SAM you can capture in practice, usually expressed as revenue or number of customers over a period (for example, 12 to 36 months).

Why it matters

TAM impresses investors, but SOM is what teams are actually held accountable for. It converts an abstract opportunity into a credible, resource-bound target.

• It grounds revenue forecasts and hiring plans in reality.
• It exposes whether a growth plan is ambitious or delusional.
• It aligns finance, marketing, and product on a shared, defensible number.

A SOM that equals your SAM signals magical thinking. A SOM near zero signals a weak position or a market not worth entering.

How it is used in practice

There are two common estimation approaches:

• Top-down: apply a realistic market share percentage to SAM, benchmarked against competitors and your channel reach.
• Bottom-up: build from unit economics (leads, conversion rates, sales capacity, average contract value) and sum to a total. This is generally more defensible.

Key inputs to pressure test:

• Sales and marketing capacity (headcount, budget, pipeline).
• Conversion and win rates from real data.
• Competitive intensity and switching costs.
• Time horizon and ramp assumptions.

Worked Example

A company sells a data governance platform.

• TAM: all organizations needing data governance globally, worth 10 billion USD.
• SAM: mid-market firms in Europe using a specific cloud stack, worth 800 million USD.
• SOM: with a 15-person sales team, current pipeline, and a 4% realistic 24-month share, the obtainable market is 32 million USD (4% of 800 million).

Bottom-up check: 300 qualified leads per year, 20% win rate, 50,000 USD average contract, over two years gives roughly 6 million USD in new annual recurring revenue, which recalibrates the share assumption downward. The gap between the two methods is the signal: reconcile it before committing to targets.