In startup market analysis, what does TAM stand for?

In startup market analysis, TAM stands for total addressable market.

TAM estimates the total revenue opportunity available if a company captured every potential customer for its product or service. Founders and investors use it to describe the broadest possible market size before narrowing the estimate.

TAM is commonly discussed alongside SAM, or serviceable available market, and SOM, or serviceable obtainable market. SAM is the portion a company can realistically serve with its business model and geographic reach, while SOM is the share it may plausibly win in the near term.

A common mistake is treating TAM as a forecast of actual sales. It is instead a ceiling or opportunity estimate, and its quality depends on clear assumptions about customers, pricing, geography, and competition. Analysts may calculate it top-down from industry data or bottom-up from customer counts and expected annual revenue per customer.