How are supplemental taxes computed?
 

Supplemental bills (or refunds) are calculated based on the number of months remaining in the current fiscal year after the month in which the supplemental event occurs. A fiscal year runs from July 1 through June 30.

If a supplemental event occurs between June 1 and December 31, only one supplemental tax bill or refund check is issued. This bill or refund accounts for the property's change in value for the period between the first day of the month following the event date and the end of the current fiscal year (i.e., the following June 30). If, however, a supplemental event occurs between January 1 and May 31, two supplemental tax bills or refund checks are issued. The second bill or refund accounts for the property's change in value for the entire 12 months of the coming fiscal year, beginning on the following July 1.