Section 138.053 - Regulation of interest adjustment provisions(1) REQUIRED CONTRACT PROVISIONS. No contract between a borrower and a lender secured by a first lien real estate mortgage on, or an equivalent security interest in, an owner-occupied residential property containing not more than 4 dwelling units may authorize the lender to increase the borrower's contractual rate of interest unless the contract provides that: (a) No increase may occur until 3 years after the date of the contract;(b) No increase may occur unless the borrower is given at least 4 months' written notice of the lender's intent to increase the rate of interest, during which notice period the borrower may repay his or her obligation without penalty;(c) The amount of the initial interest rate increase may not exceed $1 per $100 for one year computed upon the declining principal balance;(d) The amount of any subsequent interest rate increase may not exceed $1 per $200 for one year computed upon the declining principal balance;(e) The interest rate may not be increased more than one time in any 12-month period; and(f) The loan may be prepaid without penalty at any time at which the interest rate in effect exceeds the originally stated interest rate by more than $2 per $100 for one year computed upon the declining principal balance.(2) DISCLOSURES REQUIRED. No lender may make a loan secured by a first lien real estate mortgage on, or an equivalent security interest in, an owner-occupied residential property containing not more than 4 dwelling units providing for prospective changes in the rate of interest unless it has clearly and conspicuously disclosed to the borrower in writing: (a) That the interest rate is prospectively subject to change;(b) That notice of any interest adjustment must be given 4 months prior to any increase; and(c) Any prepayment rights of the borrower upon receiving notice of such change.(3) NOTICE OF INTEREST ADJUSTMENT. Notices provided under sub. (2) shall be mailed to the borrower at his or her last-known post-office address and shall clearly and concisely disclose: (a) The effective date of the interest rate increase;(b) The increased interest rate and the extent to which the increased rate will exceed the interest rate in effect immediately before the increase;(c) The amount of the borrower's contractual monthly principal and interest payment before and after the effective date of the increase;(d) Any right of the borrower to voluntarily increase his or her contractual principal and interest payment;(e) Whether as a result of the increase a lump sum payment may be necessary at the end of the loan term;(f) Whether an additional number of monthly payments may be required; and(g) The borrower's right to prepay within 4 months without a prepayment charge.(4) APPLICABILITY. (a) This section does not apply to variable rate contracts, nor to loans or forbearances to corporations or limited liability companies.(b) This section applies only to transactions initially entered into on or after June 12, 1976 and before November 1, 1981.1975 c. 387; 1981 c. 45; 1993 a. 112. "Due on sale" provision of note and mortgage was enforceable. Mutual Fed. S. & L. Asso. v. Wisconsin Wire Wks. 71 Wis. 2d 531, 239 N.W.2d 20.