Define your TAM before you build a list

Most outreach problems start before the first message is written. If the list is wrong, a sharper subject line or a better offer will not save the campaign. The fix is to agree who fits before anyone buys, scrapes or imports a single record.

Your total addressable market, or TAM, is every company that could buy what you sell. Mapping it well means writing down who belongs in it, who does not, and where to start.

Start with the customers you already have

Look at your best current customers and your most recent wins. What do they have in common? Check industry, location, company size, business model and which team signed the contract.

Then look at lost and churned deals. They show you where fit breaks down, which is just as useful as knowing where it holds.

Write the exclusions down

Exclusions matter as much as inclusions. Common ones are current customers, open opportunities, competitors, partners and markets you cannot serve. If a rule only lives in someone's head, the list will break it.

Name the buyer roles

Companies do not reply to emails. People do. For each segment, list the roles that own the problem you solve and the roles that approve the purchase. This tells you which contacts to source later, and keeps the list free of titles that cannot say yes.

Split the market into segments and tiers

A single list of thousands of companies is hard to act on. Group companies into segments that share a reason to buy, then tier them by fit. Tier 1 should look most like your best customers. Outreach starts there.

Check a sample before building the whole list

Before mapping the full market, pull a small sample that matches your criteria and review it with the people who sell. Mark the good fits and the poor fits, then adjust the rules. Fixing a definition is far cheaper than fixing thousands of records.

Keep it in one place

Write the ICP, exclusions, segments and buyer roles in one document your team can find. Note the sources used and where coverage is thin. Revisit it when your offer, pricing or best customers change.