Wis. Stat. § 905.08

A person has a privilege, which may be claimed by the person or the person’s agent or employee, to refuse to disclose and to prevent other persons from disclosing a trade secret as defined in s. 134.90 (1) (c), owned by the person, if the allowance of the privilege will not tend to conceal fraud or otherwise work injustice. When disclosure is directed, the judge shall take such protective measure as the interests of the holder of the privilege and of the parties and the furtherance of justice may require.