This is a type of liability insurance that has been designed to protect professional individuals such as medical professionals, healthcare providers, engineers, architects, lawyers, accountants, IT professionals, real estate agents, and even advertising agents.  It protects them from claims like malpractice, and errors and omissions.  Since many legal actions occur due to such, having professional liability insurance can help protect not just the financial interest, but the professional interest of that individual.  There are actually many other types of professional fields that require such protection.  If you are work as a professional that provides services to others, it is in your best interest to protect yourself with professional liability insurance.