A property manager running eleven buildings does not have one vendor compliance problem. They have eleven, wearing the same vendor names. The reason is ownership structure, and it changes what a correct roster has to look like.
Why portfolios multiply the problem
In a typical managed portfolio, each property is owned by its own entity: a per-building LLC, a partnership, sometimes a different ownership group entirely. The management company operates all of them, contracts on behalf of each, and holds the vendor relationships centrally. So the same elevator company, the same landscaper, and the same plumber work across the portfolio under one relationship and one account name.
Insurance does not follow the relationship. It follows the entities. A certificate that protects the ownership LLC at 400 Main Street says nothing about the LLC at 200 Oak Avenue, even when the same vendor mows both lawns under the same contract with the same manager.
The roster structure that matches reality
The correct structure separates two things most spreadsheets merge: the vendor identity and the per-building requirement.
The vendor identity is portfolio-level: one entry per vendor with contacts, agent information, category, and the documents that genuinely are portfolio-wide, like a trade license. Duplicating this per building creates the update problem where the vendor's new agent gets recorded in four places and missed in seven.
The requirements are building-level: for each building where the vendor works, which ownership entity must be named, what the management agreement or ownership requires for limits and coverage, and the status of the documents for that building. One vendor, one identity, several requirement rows.
Practically, this means a roster keyed on vendor-plus-building rather than vendor alone, with the exact legal name of each ownership entity recorded once, authoritatively, and reused everywhere. The entity name list is the crown jewels of portfolio compliance; most portfolio insurance failures trace back to a name that was abbreviated, outdated, or guessed.
The blanket-versus-specific question
Vendors' agents, facing a request to name several LLCs, will often respond with a blanket additional insured endorsement covering entities "as required by written contract." Whether that satisfies your requirements depends on the endorsement's actual wording and your ownership groups' expectations, and it is worth settling once, with your insurance advisor, as a standing rule: blanket endorsements accepted with these characteristics, or scheduled endorsements naming each entity required. A written rule turns a recurring judgment call into a checkable requirement.
Onboarding is where portfolios win or lose
The manager's leverage is highest before the vendor's first job. At onboarding: pull the entity names for every building the vendor will touch, put those exact names in the vendor packet, request the certificate and endorsement against them, and read what comes back name by name. The first certificate becomes the agent's template for every renewal after; getting it right once fixes years of renewals.
Then the ongoing work is arithmetic rather than architecture: a 140-vendor portfolio with per-building requirements can easily carry 300 or more document lines, each with its own renewal. That volume is exactly what request cadences and silence tracking exist for.
When buildings change hands
Portfolio composition changes: buildings are acquired, sold, refinanced into new entities. Each change ripples through the vendor roster, because every vendor at that building now needs paperwork naming a new entity. Treat ownership changes as compliance events with their own checklist, and the ripple is a week of routine requests instead of a discovery at claim time.