Bolstering attorney-client privilege, the California Supreme Court ruled unanimously Monday that factual information in lawyers’ opinion letters is as protected as the legal advice being given.

“Although exercise of the privilege may occasionally result in the suppression of relevant evidence,” Justice Kathryn Mickle Werdegar wrote, “the legislature of this state has determined that these concerns are outweighed by the importance of preserving confidentiality in the attorney-client relationship.”