The records referred to in this part and pertaining to the business of the clients serviced by the broker are to be considered confidential, and the broker must not disclose their contents or any information connected with the records to any persons other than those clients, their surety on a particular entry, and representatives of the Department of Homeland Security (DHS), or other duly accredited officers or agents of the United States, except on subpoena or court order by a court of competent jurisdiction, or when authorized in writing by the client. This confidentiality provision does not apply to information that properly is available from a source open to the public.