Final written expression: parol or extrinsic evidence
Wis. Stat. § 402.202
in effectTerms with respect to which the confirmatory memoranda of the parties agree or which are otherwise set forth in a writing intended by the parties as a final expression of their agreement with respect to such terms as are included therein may not be contradicted by evidence of any prior agreement or of a contemporaneous oral agreement but may be explained or supplemented:
(1) By course of dealing or usage of trade (s. 401.303) or by course of performance (s. 402.208);
(2) By evidence of consistent additional terms unless the court finds the writing to have been intended also as a complete and exclusive statement of the terms of the agreement.
Source: WI Statutes (Official Site)URL: https://docs.legis.wisconsin.gov/document/statutes/402.202Fetched: 10/7/2026
