An aggregate is the total of specific transactions for a specific time period. Examples include all contributions in a quarter or all expenses in an election cycle.
Aggregates for a new period restart the day after the election.
For this example, we’ll assume the itemization threshold is $100. On April 1st, May 1st, June 1st, and July 1st, you had $40 Expenses to Wal-Mart. The April and May Expenses would not itemize because expenses to Wal-Mart haven’t exceeded $100 yet. Only the June and July Expenses would itemize.