Minn. Stat. § 333.23

The secretary of state shall record written conveyances of any mark along with that part of the goodwill of the business in connection with which the mark is used, and of the corresponding application or registration which is presented for recording along with a payment of a fee of $15 and shall issue in the name of the assignee a new certificate for the remainder of the term of the registration or of the last renewal. An assignment of any registration under sections 333.18 to 333.31 shall be void as against any subsequent purchaser for valuable consideration without notice unless it is filed with the secretary of state within three months after the date of the assignment or before the subsequent purchase.