Wis. Stat. § 72.06: Confidentiality of tax returns.

Sections 71.78 (1), (1g), (1m), and (4) to (9) and 71.83 (2) (a) 3. and 3m. apply to any information obtained from any person by the department on a death tax return, report, schedule, exhibit or other document or from an audit report pertaining to the tax return.