Customer information is the most frequently claimed and most frequently contested category of trade secret.
Not protectable. The identity of customers in an industry where they are readily ascertainable from directories, trade publications or observation. A list of hospitals in a region is not a secret.
Potentially protectable. Compilations containing information not publicly available and developed at expense — specific contacts and their roles, negotiated pricing, contract expiry dates, purchasing patterns, requirements, credit terms and preferences.
Effort and expense in developing the compilation is what courts examine, and evidence of it should be preserved.
Memory. Jurisdictions differ on whether information an employee remembers, as opposed to takes, can be misappropriated. Several protect the information regardless of the medium; others treat memorised general customer knowledge as the employee’s own.
Contractual protection through non-solicitation covenants is more reliable than trade secret protection for customer relationships, and is enforceable in more states than a non-compete.
Practical measures. Restrict access to the full customer database, log exports, disable bulk export for most users, and treat a large export shortly before a resignation as the significant event it is.