This article addresses requirements software systems must meet to provide firms with adequate tools to report performance results on an after-tax basis.  In March 2003, modifications to the after-tax provisions of the AIMR Performance Presentation Standards (AIMR-PPS) were approved.  Also, the Securities and Exchange Commision has mandated that mutual funds disclose after-tax return information.  The revised AIMR standards and the SEC mandate provide a clear set of requirements for software vendors that will need to adapt their systems accordingly.  Readers that are performance and/or systems analysts executing a system search for an afte-tax  performance reporting product will obtain an understanding of how to assess the capabilities of software systems and readers that are vendors will obtain an understanding of the complexities involved in enhancing a system to meet the regulations and standards.  This information comes from the learning experience of the author, who adapted his company's system for these standards over the past couple of years.