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Who issues the most TLS certificates?
October 2026 census edition
As of October 12, 2026, the largest certificate authority by live-domain count in the Defaults.Exposed census is Let's Encrypt at 56.68% of 220.3 million certificate-presenting domains, followed by Google Trust Services at 17.80%.
Largest certificate authority: how it is measured
It comes from the certificate-issuer pass, which reads the issuer field of every certificate presented to the census and attributes it to the authority that signed it. Every domain in the census is measured directly and counted once.
Certificate authority share is attributed from the issuer field of certificates actually presented, so it measures live deployment rather than certificates sold. Because of that concentration, the largest authorities’ policies on validation and lifetime propagate to a large fraction of the web.
The figure is a name rather than a number: whichever entry holds the largest share of the population being measured, with that share stated beside it.
It moves when hosts enable HTTPS (Hypertext Transfer Protocol Secure), renew or misconfigure certificates, and when platforms change what they negotiate by default. Most of the movement here comes from platform defaults. The number is recomputed from the raw evidence at every edition. What it cannot tell you is where one particular domain stands: for that, see fix your TLS setup.
the full grading methodology · the underlying dataset, published open with the counts behind every percentage. If a figure here disagrees with one elsewhere on the site, the dataset is canonical and we would like to know.
| Certificate authority | Domains | Share |
|---|---|---|
| Let's Encrypt | 124,837,486 | 56.68% |
| Google Trust Services | 39,207,201 | 17.80% |
| GoDaddy | 26,754,374 | 12.15% |
| Sectigo | 9,073,676 | 4.12% |
| DigiCert | 4,996,558 | 2.27% |
| ZeroSSL | 2,930,760 | 1.33% |
| Amazon | 1,709,101 | 0.78% |
| GlobalSign | 1,417,260 | 0.64% |
| Actalis | 1,156,217 | 0.52% |
| TrustAsia | 573,307 | 0.26% |
Largest certificate authority: how to cite it
Please cite Defaults.Exposed and link this page. The citation below carries the date.
Defaults.Exposed, "Who issues the most TLS certificates?" (as of October 12, 2026). https://defaults.exposed/stats/who-issues-the-most-tls-certificates
Permalink: https://defaults.exposed/stats/who-issues-the-most-tls-certificates · Machine-readable: /stats/s/biggest-ca.json · Licence: open data
Methodology: how we grade the internet · Source data: census data and downloads. Updated with each census edition.