Whether you're making a pitch to investors or building a business case for a new product line, if you want “buy-in,” you’re going to need data. More specifically, you need the most defensible estimation of your product or service’s TAM, SAM, and SOM .    But what do TAM, SAM, and SOM stand for, and why are they valuable?   At the highest level, these three TLAs (or three-letter acronyms) form the framework that tells the story of your market opportunity.  Together, they show