Public Liability (PL) or Employer's Liability (EL) insurance may be mandatory for a company based on factors such as the business nature, local regulations, and industry standards. Public Liability insurance covers claims from third parties for injury or property damage due to business activities, while Employer's Liability insurance is required in many countries to protect employees in work-related incidents. To determine if PL or EL insurance is necessary for your company, consult an insurance expert or legal advisor for tailored advice based on your business requirements and location.