A Common Mark Certificate (CMC) is a type of certificate used with BIMI for organisations that want to display a logo but do not hold a registered trademark for it. It complements the VMC, which requires a registered trademark.
CMCs widen logo eligibility to marks that cannot meet the strict trademark test, such as government and public-body emblems or logos validated through evidence of prior use rather than registration. Like a VMC, a CMC is issued by an approved Certification Authority after identity validation, and it carries the logo as an SVG Tiny PS image.
Support varies by mailbox provider, and historically a CMC may not unlock logo display everywhere a VMC does, so check current provider requirements before relying on one. The certificate URL is published in the BIMI record's a= tag, alongside the logo location in l=.
As with any BIMI deployment, a CMC only takes effect once the domain enforces DMARC at p=quarantine or p=reject with passing alignment. Without enforcement the logo stays hidden. Verify your BIMI record and certificate with the checkers below before publishing.
Check it on your domain
- CMC Simulator: preview a Common Mark Certificate logo in the inbox.
- BIMI Checker: check a domain's BIMI record, logo and VMC.
- BIMI & VMC Checker covers end-to-end BIMI readiness: DMARC enforcement, record, logo and VMC.