Also called: Total Addressable Market
TL;DR
Total Addressable Market, the total revenue opportunity if the product captured 100% of every customer who could conceivably buy it.
TAM is the upper bound of the market opportunity, calculated as if the company had no competition and no friction. It's the headline market-size number on most pitch decks and the most commonly inflated.
A defensible TAM is built bottoms-up: count the eligible customers, multiply by realistic ACV, and show the math. Top-down TAM (analyst report says the market is $X) is widely distrusted because it rarely maps to the company's actual ICP.
A vertical-SaaS targeting US dental practices: 200,000 practices × $12,000 average annual software spend = $2.4B TAM. Investors will discount 'top-down' TAM heavily; pair it with a bottoms-up build for credibility.
The Market slide should show TAM, SAM, SOM in nested format with a defensible bottoms-up calculation behind at least one of them.
TAM shows up most often in these scoring rubrics and investor profiles, jump straight to who cares about it and how to pitch them.
Serviceable Addressable Market, the portion of the TAM that the company's product, geography, and channels can realistically serve.
Serviceable Obtainable Market, the realistic share of SAM the company can capture in a defined planning horizon.
Calculating market size by counting the actual eligible customers and multiplying by realistic per-customer revenue.
Estimating market size from a published total (analyst report, government data) and applying assumed share percentages.
A precise definition of the buying organization that gets the most value from your product and is the cheapest to acquire.
Long-form deep dives on the slides TAM most often shows up on.
Deckmetric scores your pitch across 10 VC frameworks and against 8 investor types.