According to the Attorney General's opinion of the State of Michigan, taxes are levied for a calendar year and are collected for the calendar year in which the levy is made, therefore making them paid in arrears. For instance, the taxes that is assessed and levied in 2017 are for the year 2017. The taxing authority may spend the taxes in 2018, but that does not change the fact that they are 2017 taxes. However, the above does not mean that buyers and sellers cannot agree to prorate the taxes on a property transaction in a different manner.
MCL 211.2 of the General Property Tax Act provides that buyers and sellers may agree to prorate taxes in any manner in which they see fit. If a buyer and seller, between themselves, agree to treat taxes as though paid in advance, then that is how the taxes are to be prorated. If this method were used, then the buyer would be totally liable for a tax bill issued later in the calendar year in which the property was purchased. If they agree to treat the taxes as paid in arrears, that tax bill along with any earlier tax bill issued for that year is combined and prorated according to how long each party owned the property that year.