The loss of privilege can occur where (i) there is loss of confidentiality; (ii) privilege is waived intentionally; (iii) the clients or their lawyers attempt to make some limited use of privileged documents without reserving privilege; or (iv) when a partial disclosure of privileged documents occurs. It can also occur when a third party is able, by whatever means, to produce secondary evidence of the contents of a privileged communication.

There are limited exceptions where sharing a document may not result in the waiver of privilege. 

Partial waiver

The Hong Kong Court of Appeal in Citic Pacific Limited v. Secretary for Justice and Commissioner of Police [2012] 2 HKLRD 701 held that Hong Kong law recognizes the concept of partial waiver of privilege. A privileged document may be disclosed to one party for a limited purpose, thus waiving the privilege to that document as against that party alone only for the specified purpose. However, the privilege to the document is retained as against all other third parties. In order to maintain the privilege, it is important to specify in writing at the time the privileged document is disclosed that it is provided confidentially and the purpose for which the privileged document is disclosed.  The scope of the disclosure should be sufficiently limited so that a wider blanket waiver is not implied.

In this case, the Court of Appeal rejected the Hong Kong Secretary for Justice’s contention that when prosecuting authorities come into possession of privileged documents, privilege will be lost, and the information would be available for use by the authorities regardless of how the authorities came about the information. The Court of Appeal made clear that privilege is recognized in the Basic Law of Hong Kong as a substantive legal right of particular importance to the due and just administration of justice. Privilege is not lost unless there is evidence that it has been intentionally waived by the holder of that privilege, and a waiver will not be lightly inferred.

Common interest privilege

Common interest privilege arises where one party confidentially and voluntarily discloses the privileged document to another party, who has a common interest in the subject matter of the communication at the time of disclosure. The document will remain privileged, with privilege belonging to the original party, despite the fact it has been shared. The privilege can only be waived by the original party.

Joint privilege

Joint privilege can arise in two circumstances: (i) through a joint retainer; or (ii) by sharing a joint interest in the subject matter of the communication at the time that it comes into existence. The effect of joint privilege is that each party is entitled to benefit from all privileged communications and neither party retains any confidence against the other. Both parties need to agree to waive privilege, and disclosure of privileged communications by one party will not automatically result in the waiver of privilege over the document.