GUIDE

Map your TAM with look-alike data

Top-down TAM ("the market is $40B") impresses nobody who's diligenced a deck before. Bottom-up TAM — a countable list of real companies that resemble your actual buyers — is defensible, actionable, and buildable in an afternoon.

The method

Seed with reality. Take every customer you've closed (or your 20 best). These define what your buyer actually looks like — no personas required.
Expand each seed. Bulk-research all seed domains with SimilarIQ — up to 100 ranked look-alikes per seed, with match scores and confidence.
Dedupe and threshold. Merge on domain. Companies appearing under multiple seeds with scores ≥ 80 are core TAM; 60-79 is expansion TAM.
Count and value. Core TAM count × your ACV = a bottom-up number backed by a literal list of company names you can put in an appendix.
Recurse to saturation. Feed high-scoring look-alikes back in as seeds until new-company yield drops below ~20% — that's your market boundary, empirically found.

Why investors prefer this

A named-company TAM survives diligence: anyone can sample the list and check that the companies are real and plausible buyers. It also converts directly into a sales plan — the TAM list is the target-account list, exportable to CSV, Salesforce, or HubSpot.

Frequently asked questions

What's the difference between top-down and bottom-up TAM?

Top-down starts from an analyst's market size and slices downward with assumptions. Bottom-up counts actual target companies and multiplies by realistic deal value. Bottom-up is more defensible because every company on the list can be verified.

How do I know when my TAM map is complete?

Recurse: feed high-scoring look-alikes back in as new seeds. When a round of expansion yields fewer than ~20% new companies, you've saturated the market boundary.

How much does it cost to map a TAM this way?

Each seed search is 1 credit (up to 100 look-alikes). A 20-seed map with two expansion rounds is typically 60-100 searches — under $50 pay-as-you-go, less on a plan.

Try it now: enter any domain at similariq.ai and get the top 100 competitors, look-alikes, and similar companies in about a minute — free trial searches included.