For financial reports, the time zone is always set in UTC (Universal Time Coordinated) so that it corresponds exactly with the accounting and remittance processes used at ACTIVE.com. For example, a report set for January 1 - January 15 will locate all transactions from January 1 at 12:00 am UTC through January 15 at 11:59 UTC.
Due to the difference between your local time zone and UTC time, a few transactions from outside of your expected time period may appear at the beginning/end of your report.