This document discusses how to conduct a market analysis to identify the total available market (TAM) size for a new product or service. It recommends determining the current TAM, growth rate, factors driving market trends and adoption, as well as competition and market structure. Examples are provided showing how to estimate the server virtualization TAM using top-down and bottom-up approaches, as well as the potential market for plug-in hybrid electric vehicles using a comparable method. The document stresses the importance of citing reliable data sources and providing realistic market projections to convince investors of the opportunity size.