Certificate expiry · UK small companies

What share of UK small companies have a TLS certificate expiring within 30 days, or expired?

7.07%

7.07% of UK small companies (95% CI 5.42–9.18%), measured across 721 companies on 2026-08-12.

valid (>30d): 92.93%expiring <30d: 7.07%
valid (>30d) · 92.93%expiring <30d · 7.07%
Trend

Measured every Wednesday since 2026-08-01 — 4 observations to date. Last measured 2026-08-12.

How this is measured

Tier 2, one TLS handshake; read not_after. Denominator: has_web.

Passive measurement: a single DNS lookup, TLS handshake, or homepage GET per domain. Aggregate-only; no individual company is named. 95% Wilson confidence intervals. Population: national company registries (Companies House, Brreg, SIRENE), sampled by size band and resolved to email-active domains. Parked domains excluded. Snapshot: uk-companies-house-per600-seed20260728.

Licensed CC BY 4.0 — reuse with attribution to Quiet Failures. Download: JSON · CSV.

Why it matters

The certificate nobody owns. Expiry is a scheduled, entirely predictable outage that still takes sites down constantly, because renewal was somebody's manual task and that somebody left.

The same check, other segments

Show the remaining 64 segments

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