"controlled business" is most accurately described as

Controlled business pertains to taking out life insurance or annuity contracts covering the agent or family members; officers, directors, stockholders, partners, or employees of a business in which he or she or a family member is engaged; or the debtors of a firm, association, or corporation of which he or she is an officer, director, stockholder, partner, or employee.
In other words, "Limiting sales to a specific group in which you have a vested interest ."