The Contact Data Decay Report 2026
How fast B2B contact data goes stale — and what an un-cleaned list costs you a year later.
Key findings
- ◆A typical B2B email list loses ~22.5% of its deliverability in a year.
- ◆Contact data decays about 2% per month — slow enough to ignore until it hurts.
- ◆By 12 months, roughly 30% of an un-cleaned list is undeliverable.
Why contact data decays
People change jobs, companies change domains, mailboxes get deactivated, and phone numbers get reassigned. None of it shows up in your CRM until an email bounces or a call fails — by which point the damage to your sender reputation is already done.
The decay isn't dramatic month to month, which is exactly why teams miss it. At roughly 2% a month it compounds quietly until a quarter of the list is dead.
What decay costs
- Higher bounce rates throttle your sending reputation with Gmail and Yahoo.
- Sales teams waste hours on contacts that no longer exist.
- Reporting is skewed — open and reply rates are measured against dead addresses.
- Re-engagement and win-back campaigns underperform because a chunk of the audience is unreachable.
How to stay ahead of it
The fix is routine, not heroic: re-verify any list older than 90 days, verify at the point of capture so bad data never enters the CRM, and clean purchased lists before the first send.
Methodology: Illustrative analysis modelled on industry decay rates across a sample of business contact lists. Figures are illustrative and will be updated with live anonymized data. Free to cite with attribution to BounceBlock.
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