A corporate group can centralise BIMI operations without treating every subsidiary as the same sender. The important unit of planning is the sending identity and its approved brand, not the number of companies in the organisation chart. Start by deciding which domains should represent the parent and which should retain a subsidiary mark.
Build a domain-to-brand register
For each visible From domain, record the business owner, approved logo, sending systems, certificate coverage and public asset URLs. Include subsidiaries with separate brands, joint ventures and recently acquired businesses. Corporate affiliation alone does not settle whether a particular mark may be asserted by a given domain or whether an existing certificate covers it.
Use issuer documentation for certificate scope. For example, DigiCert's lifecycle workflow explicitly represents domain names in its certificate request and reissue processes. That supports checking the actual issued scope rather than assuming a parent-company certificate automatically covers every subsidiary. Issuer-specific commercial and validation terms must be confirmed separately.
Delegate responsibility without losing review
A central mail team can maintain templates and monitoring, while local brand owners approve the appropriate image and legal contacts establish rights. Document who can change a subsidiary's DNS assertion and who can publish files to a shared asset host. Do not allow a default configuration to substitute the parent logo whenever a subsidiary mapping is missing.
The shared host should serve a deliberate file for each approved URL. Separate tenant paths and maintain a release manifest so an update for one business does not silently overwrite another business's asset. These are recommended change controls, not additional BIMI protocol tags. Their value is limiting mistakes across an otherwise efficient shared service.
Test a three-domain portfolio
In a synthetic register, example.com uses the parent mark, retail.example uses a separate retail mark, and service.example uses the parent mark under an approved relationship. Each row records the intended logo digest and certificate coverage. A review catches retail.example pointing to the parent file after a shared-host deployment. The DNS text is syntactically plausible, but the domain-to-brand mapping is wrong.
A second negative case removes service.example from the documented certificate scope while leaving its assertion unchanged. Flag it for issuer and technical verification rather than deciding that corporate ownership cures the mismatch. A local register test can identify inconsistent inputs; it does not verify legal eligibility or a certificate chain. Those checks need their own evidence and reviewers.
Measure coverage by identity and receiver
Ask whether each active identity passes its authentication prerequisites, publishes the approved assets and has been observed at the intended receivers. A portfolio with ten DNS records is not necessarily ten verified deployments. Keep incomplete identities and unsupported or untested receiver surfaces visible in the rollout report.
BIMI Group's implementation guidance leaves display criteria to participating providers. Therefore, do not promise group-wide logo appearance solely because a central service is healthy. Recheck the register after acquisitions, divestitures, domain transfers and shared-host changes. Remove authority that no longer belongs to a former subsidiary without disrupting retained operational mail. The portfolio above is invented; no production DNS, certificate or receiver evidence is claimed.
Use separate approval and evidence columns
A portfolio row should carry a brand approval reference as well as its technical evidence. A shared logo may be appropriate for two domains, but do not infer that a certificate purchased for one automatically covers the other. DigiCert explicitly lists domains in the request and warns that additional domains may affect validation and cost. Commercial approval remains separate from this planning worksheet.
- Visible From domain, subsidiary and accountable owner: pending.
- Approved mark and rights approval reference: pending.
- Issued certificate domain scope and issuer confirmation: pending.
- Public logo/certificate URL, expected digest and observed digest: pending.
- Shared-host change owner, affected sibling domains and rollback boundary: pending.
- Tested sender/receiver pairs, untested identities and review date: pending.