Several working committees in the TIGERS XML Work Group have developed draft XML schemas relating to "an XML-based tax data submission process for use by all state and federal tax authorities." The US Tax Information Group for ECommerce Requirements Standardization (TIGERS) work group has been chartered "to discuss matters relating to business standards and practices surrounding national tax data formatting and transfer; it develops and maintains tax electronic technical format standards for a variety of tax filing and other related government electronic reporting or data exchange applications." The TIGERS project web site provides public access to draft schemas for IRS Form 1120 (140 XML schema files) and for Form 1120S (Subchapter S Corporation). IRS Form 1120 for US Corporate Income Tax Return was initially selected for the pilot because it represents approximately 85% of the data elements for IRS filings, and has significant overlap with the Individual Income Tax Form (1040). The IRS 1120, 1120S, and 941 schemas are now being reviewed, supported by a listserver; ongoing work includes the development of IRS Form 1041, 1065, and 990 XML schemas. Working committees have also prepared a draft 'eFile Transport and Packaging Proposal' which "outlines a method for enveloping XML data designed to provide utility in securing, receiving, routing, and processing files; the intent of the exercise is to determine how best to package for transmission and subsequent processing XML-format 941s, 1120s, and other transactions."

A report of 2001-11-07 by Dr. Glenda Hayes (MITRE) summarizes XML Schema Activities at IRS. The main example outlines the current approach taken in the creation of an IRS 1120 XML schema, where "one of the main objectives is to validate numeric values, as appropriate." Using XML schemas and XSL should reduce data errors, reduce costs in tbe validating of returns, and support easier transitions for changes in tax forms/schedules. The benefits of using XML for IRS 1120 [US Corporate Income Tax Return] are that "1120 represents approximately 85% of the data elements for IRS; it has significant overlap with Individual Tax (1040); the design effort will reconcile duplicate data elements (e.g., string length for address); it meets external stakeholder request; represents an IS/ETA joint effort; is a scoped pilot; exploits a large base of developers; involves coordination with external groups." Three experimental approaches to tax XML Schema development were identified: (1) using XBRL [loose control]; (2) a derived EDI based/TIGERS approach, with schema patterned after EDI transaction; (3) a 'direct' approach with tight control, patterned after the Microsoft 1040 strawman and the TIGERS Sales Tax Group. Draft schemas have been posted for public review. Next steps for IRS development are (1) community review of the 1120, 1120S, 941 schemas; the IRS has now set up a listserv for this purpose; (2) development of IRS Form 1041, 1065, and 990 XML schemas; (2) refinement of IRS XML schema, both types and general elements. [adapted from the report and TIGERS October minutes]