​January 21, 2021

To: Manufacturers, Manufacturing Property Owners, and Preparers Filing M-Forms

The Wisconsin Department of Revenue (DOR) has opened its electronic (e-filing) system to manufacturers required to file 2021 Manufacturing Personal Property (M-P) and Real Estate (M-R) Returns (M-Forms). Companies leasing personal property to state-assessed manufacturers should file the Leased, Rented or Loaned Personal Property (M-L) Return. Visit the Manufacturers page on DOR's website for more information on 2021 M-Forms.

Notes for 2021:

• Federal Government (IRS) safe harbor and de minimis safe harbor standards that provide guidance for federal income tax deductions do not apply to Wisconsin state personal property tax reporting. Review the 2021 M-P Form Instruction Booklet (page 5) for more information.
• You cannot access the Manufacturing Assessment System (MAS) login page from a favorite/bookmark

Helpful Reminders:

• DOR strongly encourages you to electronically file (e-file) your M-Forms
  • 2021 M-Forms are now available to authorized users of our electronic filing system (MAS)
  • See Getting Started Instructions
  • M-Form filing instructions and common questions on are located on our website


• E-filing benefits/tips
  Getting started:
  • MAS users are notified of approaching deadlines and missing (late) returns
  • If you e-filed last year, your 2021 M-Form pre-fills with last year's data
  • After logging into DOR's MAS system, electronic filers should download a copy of the M-Form to their computer. Locate the downloaded form and save it to your computer.
  ​ Additional information:
  • Attachments – you can attach files to submit with the electronic form, including: asset lists, building plans or any additional information
  • The form prints as it appears on screen
  • M-P Form displays all physical locations within each municipal account
  • Status of electronic filings is tracked within the system and displayed on an account history page or authorized accounts page
  • You can review your audited forms (current and prior years) after assessments are finalized


• Paper filing your return
  • DOR encourages past paper-filers to try e-filing for greater efficiency, accuracy and verification of filing
  • M-Forms to download and print will not be available on our website until February 1


• Filing extension requests – by March 1
  • Electronic – the easiest way to file an extension request is online. File your request within the electronic filing system on an individual account basis, by March 1. You will receive immediate confirmation after you submit your extension request.
  • Mail, fax, email – filing extension requests received by mail, fax, or email must identify each individual account and be received by, or postmarked, on or before March 1

For other questions on manufacturing property assessment, contact the Manufacturing & Utility Bureau District Office in your area.