Alaska Sales Tax Cap

While the State of Alaska does not collect sales tax many of the boroughs and cities do.  Some of the boroughs and cities have a maximum (cap) on the amount of sales tax that can be collected on a sales transaction for special customer groups.  As an example, the maximum sales tax that can be collected is $15 on a single transaction.  Has anyone encounter this problem and if so were you able to handle the cap using standard JDE tax set up?