§ 9.16. Interest on Late Payment of Taxes:

All taxes paid on or before the thirty-first day of August shall be collected by the Treasurer without additional charge. On September first he shall add to all taxes paid thereafter four percent of the amount of said taxes and on the first day of October and of each succeeding month he shall add an additional one-half of one percent of said taxes that remain unpaid. Such penalty shall not exceed six percent and shall belong to the city and constitute a charge and shall be a lien against the property to which the taxes themselves apply, collectible in the same manner as the taxes to which they are added. It is provided, however, that if delivery of the tax roll to the Treasurer, as provided in Section 9.13, is delayed for any reason by more than thirty days after June first, the application of the penalty charge provided herein shall be postponed for the first thirty days of such delay and shall be postponed an additional thirty days for each additional thirty days, or major fraction thereof, of such delay.

State law reference

Interest on unpaid taxes, MCL 211.44, MSA 7.87.