Wis. Admin. Code Department of Financial Institutions DFI-WCA 1.35
In cases where a person assumes liability on an open-end account, paragraph (a) of the Explanation of Personal Obligation under s. 422.305, Stats., shall be modified to read as follows: "(a) You have agreed to pay amounts owing or to be owing in the future as a result of charges made by (name of customer) on his or her charge account with (name of creditor) in an amount not exceeding $ ." Paragraph (b) of the Explanation must contain the following statement: "If you wish to terminate your guarantee with respect to future transactions, you must notify (name of creditor) in writing." An explanation of the form described in this rule will satisfy the requirements of s. 422.305, Stats., and no further notice or Explanation of Personal Obligation need be given the person with respect to subsequent individual purchases or loans on the account. However, in case of any subsequent change in the terms of the account which would increase or extend the contingent liability of the person, where the merchant was authorized to make unilateral changes from time to time under the original terms of the account, an explanation of such change must be given to the person in accordance with s. 422.415, Stats. Such notice shall conspicuously disclose that if the person wishes to terminate the guarantee with respect to future transactions, the person must notify the creditor in writing.
Wis. Admin. Code Department of Financial Institutions DFI-WCA 1.35