All Markets Are Not Created Equal (Note to Self on TAM)
Bill Gurley · 2012
"Ten factors determine whether a digital marketplace can become large and durable; not all TAMs are equal."
'Total Addressable Market' (TAM) is often used as a single big number to justify a startup's potential — 'the market is $50 billion, so we could be huge.' Gurley's point is that the size of the market on paper tells you almost nothing on its own; what matters is the structural quality of that specific market — things like whether the product is used frequently or rarely, whether the marketplace naturally consolidates around one winner, whether there's real network effects, and whether new supply/demand can be added cheaply. Two markets can have the identical dollar-figure TAM and be wildly different investments.
The mechanism is that market size is necessary but not sufficient — you also need the market's dynamics to funnel value toward a durable winner rather than getting split thin across many players or captured by suppliers. Gurley lists structural questions like: is usage frequent (keeps you top of mind) or rare (users forget you exist between purchases)? Is there a natural mechanism pushing toward one dominant platform (network effects, data advantages) or does the market stay fragmented forever? Can the company acquire supply and demand cheaply, or does each side require expensive, one-off sales effort? A large TAM with poor answers to these questions can still produce a mediocre business.
What is Bill Gurley's central warning about using TAM (Total Addressable Market) to judge a startup?
Read more about the topic
The explanation above is written with AI assistance. These are the originals — go to them to check it.
- All Markets Are Not Created Equal (original essay)Above the Crowd — Bill Gurley
- The Bill Gurley Chronicles: VCs, marketplaces, and early-stage investingEquity Mates
- Bill Gurley's thoughts on marketplaces are a must readFabrice Grinda
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