Legal Definitions - subject-matter waiver

A subject-matter waiver is a type of waiver where a party voluntarily discloses a communication or privileged material about a particular topic to a third party. This may lead to an implied waiver that extends to all other communications relating to the same subject matter.

For example, if a company voluntarily discloses a confidential email about a specific project to a third party, a court may find that the company has waived its privilege over all other communications related to that project. This means that the company cannot claim privilege over any other emails, documents, or conversations related to the same project.

Another example of subject-matter waiver is in the context of attorney-client privilege. If a client discloses a communication with their attorney about a specific legal issue to a third party, a court may find that the client has waived their privilege over all other communications with their attorney related to that legal issue.