TAM in SaaS Investing

This question tests whether you understand how investors think about scale in SaaS businesses. TAM helps frame the revenue opportunity a company can realistically pursue, which is important because software companies are often valued on their ability to capture a large and growing market. Interviewers ask this to see if you can connect market sizing to growth potential, customer segmentation, and the quality of the assumptions behind an investment case.

It also checks whether you know the main approaches to sizing a market. A bottom up view builds from customer level economics, such as the number of target users or customers and the revenue they can generate, while a top down view starts with a broader industry estimate and narrows it using assumptions about share and fit. Strong candidates should explain the logic behind each method, when one is more useful than the other, and why TAM is an input for evaluating opportunity rather than a precise forecast.