Wis. Stat. § 30.576: Method of perfecting exclusive.

(1) Except as provided in sub. (2) and subject to s. 409.311 (4), the method provided in ss. 30.57 to 30.575 of perfecting and giving notice of security interests subject to those sections is exclusive. Security interests subject to ss. 30.57 to 30.575 are exempt from the provisions of law that otherwise require or relate to the filing of instruments creating or evidencing security interests.

(2) Subsection (1) does not affect the validity of a security interest perfected before January 1, 1992.