Not a marketing figure — a reproducible overlap test. Here's exactly what we did, what we found, and where the number could move.
We drew 1,000 contacts at random from the Datasigma index — not hand-picked. They span 991 distinct companies (about one contact per company), so the result isn't skewed by a handful of accounts.
For every contact we queried Apollo by full name + company domain — the same way a rep prospecting that person would. We recorded whether Apollo returned a matching person record.
Matched = Apollo returned a person at that company for that name. No match = Apollo returned zero results. We did not count partial or wrong-person hits as matches.
We manually re-ran a random subset of the "no match" contacts by hand in Apollo's own UI to confirm they were genuine gaps — not query errors on our side. The 58.3% reflects real absences from their database.
Of the 417 contacts Apollo did have, a large share were missing the details that make a contact actionable — no email or no direct dial on the record.
Breaking the same 1,000 lookups down by seniority shows a clear pattern — Apollo thins out fastest on the owners and founders who actually sign off on deals.
A random draw across markets, industries, and seniority — so the number reflects the database as a whole, not a favorable slice of it.
It's a sample, not a census. At 1,000 contacts the result carries a margin of about ±3% at 95% confidence — so the true figure sits in roughly the 55–61% range, not exactly 58.3%.
Apollo's coverage varies. Results can differ by region, plan tier, and over time. This is a snapshot of what Apollo returned at the time of testing (August 2026), not a permanent claim.
"No match" means no match on name + domain. A contact absent from Apollo may still exist on another platform. This test measures overlap with Apollo specifically — which is why it runs higher than our broader "on no other platform" figure.
You don't have to take our word for it. Every Datasigma contact links to the public page it was sourced from — so you can verify any record, and re-run this comparison against your own tools.
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