• Federation of Tax Administrators Corp Efile Development Page
• Guide For Electronically Filed Corporation Franchise & Income Tax Returns | Word format
• Wisconsin specific eFile Types supporting schema (XSD format)
• IRS efileTypes.xsd

Supporting Schedules

• Form 4B Apportionment Data
• Form 4BL Net Business Loss Carryforward and Instructions
• Form 4U Underpayment of Estimated Taxes by Corporations and Instructions
• Schedule R Research Credits
• Schedule V Additions to Federal Income
• Schedule W Subtractions From Federal Income
• Schedule Y Deductible Dividends
• Schedule Z Manufacturer's Sales Tax Credit
• Schedule Z-1 Manufacturer's Sales Tax Credits Passed Through From Other Entities and Instruction

• Form 4 Sample Wisconsin instance document (XML format)
• Wisconsin specific Form 4 schema
• Wisconsin Form 4 Specifications Detail Spreadsheet (XLS format)
• Form 4 Corporation Franchise or Income Tax Return

• Form 5 Sample Wisconsin instance document (XML format)
• Wisconsin specific Form 5 schema
• Wisconsin Form 5 Specifications Detail Spreadsheet (XLS format)
• Form 5 Corporation Franchise or Income Tax Return

• Form 5S Sample instance document (XML Format)
• Wisconsin specific Form 5S schema
• Wisconsin Form 5S Specifications Detail Spreadsheet (XLS format)
• Form 5S Tax-Option (S) Corporation Franchise or Income Tax Return
• Schedule 5K-1 Tax-Option (S) Corporation Shareholder's Share of Income, Deductions, etc.