In various jurisdictions, individuals or entities can act as retainers (or retainership holders) beyond licensees:

Individuals

1. Legal professionals (e.g., attorneys, solicitors)
2. Certified public accountants (CPAs)
3. Registered agents or representatives
4. Trust officers
5. Bankers or financial advisors

Entities

1. Law firms
2. Accounting firms
3. Trust companies
4. Investment advisory firms
5. Corporate entities (with necessary licenses and permissions)

Requirements

1. Relevant expertise and experience
2. Professional certifications or licenses (if applicable)
3. Good reputation and integrity
4. Compliance with regulatory requirements
5. Agreement with the licensee (retainer agreement)

Examples

1. A lawyer retains a paralegal or law clerk to assist with client matters.
2. A CPA retains an accounting firm to provide audit services.
3. A bank retains a trust officer to manage client accounts.

Key Considerations

1. Clarify roles and responsibilities
2. Establish communication channels
3. Define scope of work and compensation
4. Ensure confidentiality and data protection
5. Comply with regulatory requirements

Please specify the jurisdiction or context for more tailored information.