B2B Email Data Quality: We Analyzed 134,653 Verified Emails

Data quality is the backbone of B2B prospecting: sending to invalid addresses drives up your bounce rate and damages your sender reputation. But how reliable are B2B email lists in practice? We analyzed 134,653 professional emails that went through Listar's verification engine. The results speak for themselves.

Nearly 1 in 4 B2B emails is invalid

Of the 134,653 verified emails, only 64.8% are confirmed valid and deliverable. 23.7% are outright invalid — nearly one address in four. And 11.4% come back "inconclusive": the receiving server doesn't allow a clear verdict.

In other words, more than a third of emails (35.2%) cannot be considered safe to send without prior verification.

Why so many emails are invalid

Behind the "invalid" verdict are several concrete causes that verification surfaces:

• Non-existent mailbox: the address has valid syntax but the mailbox doesn't exist (typo, the person left the company, or a wrongly-guessed format).
• Domain with no valid mail server: no MX record — the domain simply cannot receive email.
• Generic (role-based) addresses: contact@, info@, support@ — rarely real people and often filtered.
• Disposable or personal addresses: temporary services and free mailboxes wrongly used in a B2B context.

These errors are invisible to the naked eye: a well-formatted address can lead nowhere at all.

The "catch-all" server trap

The 11.4% of "inconclusive" emails largely correspond to catch-all domains: they accept every incoming email, valid or not. A simple check cannot tell them apart — it returns "accept-all" without confirming the mailbox actually exists.

This is where single-level validation hits its limit: only multi-source cross-checking can decide on these addresses.

What it means for your prospecting

If you import a "raw" list and send it as-is, you can expect roughly a quarter of your messages to bounce. Beyond a few percent of bounces, mailbox providers degrade your deliverability — including for your legitimate emails.

The fix: verify every address before sending. You can test one address for free with our email verifier, or validate an entire list at once with Listar.

Methodology

Analysis of 134,653 professional emails that went through Listar's verification engine (syntax, MX record and mailbox-existence checks). The sample reflects emails from B2B prospecting (provided or reconstructed), not a random draw of all professional emails: exact proportions may vary by source. Aggregated data — no individual address is disclosed. Figures as of June 2026.

Frequently asked questions