Introduction

A B2B contact database can lose accuracy even when marketers do nothing wrong. Employees change jobs, businesses close or rebrand, domains are replaced, and professional email addresses become inactive. The latest ZeroBounce 2026 Email List Decay Report, based on more than 11 billion email addresses processed during 2025, found that at least 23% of email-list data decayed within one year. (ZeroBounce)

That does not mean exactly 77% of small-business contacts remain valid: ZeroBounce's study covers businesses of different sizes and industries rather than small businesses specifically, and its decay measure includes risky records as well as outright invalid addresses.

Still, the finding provides a useful benchmark for anyone managing a Small Businesses Email List. This article examines what the 12-month decay evidence means for SMB prospecting, why business contact data changes, and how marketers can keep a Small Businesses Email Database usable over time.

What Percentage of Contacts Remain Valid After 12 Months?

The best current broad-market benchmark indicates that at least 23% of an email list can degrade over a 12-month period, leaving approximately 77% outside that measured decay category. However, marketers should not describe 77% as a guaranteed validity rate.

ZeroBounce analyzed email addresses verified between January and December 2025 and reported that at least 23% of email-list data degraded within one year. The company also notes that its customer base ranges from solo business owners to large enterprises, meaning the result represents a cross-section of business sizes and industries rather than a dedicated small-business cohort. (ZeroBounce)

This distinction is important.

ZeroBounce's historical comparison shows decay at 23% in 2021, 22% in 2022, 25% in 2023, 28% in 2024, and 23% in 2025. (ZeroBounce)

The practical conclusion is more useful than the headline percentage: a contact list should not be treated as a static asset.

Why the 23% figure should not be called a small-business-specific rate