General Information - Software Developer Specifications for ST-12

Filing and Paying Timely

For transmitters with an early monthly filing status, the transmission and payment are due on the 20th of the month following the close of the period. For all other transmitters, the transmission and payment are due on the last day of the month following the close of the period covered by the return. If the due date falls on a weekend or state holiday, the due date is extended to the next regular business day. Transmissions must be received by the due date and should be transmitted prior to the 11:00 PM CT cut-off on the due date.

If paying by EFT, the EFT payment must settle in the state account on or before the due date in order to be considered timely. The EFT debit payment included in the file transmission must be initiated by 3:00 PM CT on the banking business day prior to the requested settlement date/due date.

Note: A separate EFT Credit or EFT Debit Independent of the Sales File Transmission payment must also be initiated on the return due date by 3:00 PM CT on the banking business day prior to the requested settlement date

Data Requirements

Zero or Blank Fields - You do not need to transmit any optional element that has a zero or is blank. Send data elements only if they contain data values. Do not send empty data elements (i.e., zero financial fields, unused elements, etc.).

Payment Methods

Sales and use tax registrants using the file transmission method must make payments electronically by including Electronic Funds Transfer (EFT) information either in the file transmission or independent of the file transmission process. The following options are available:

Note: You may not pay by paper check in the Sales File Transmission process. Registrants should not submit a check to WDOR. If a check is mailed, WDOR cannot guarantee proper or timely processing of the check.

Adjustments and Changes to Returns

WDOR reserves the right to review the transmission, including the retailer’s discount, late filing fee, interest, and penalty reported in the transmission. This review may result in a Notice of Amount Due or Refund. In these cases, WDOR will issue a Notice of Adjustment with a tear-off payment voucher. This notice is mailed directly to the sales tax registrant. If the sales tax registrant agrees with the notice, the amount due should be mailed with the tear-off payment voucher to the address on the voucher. Appeal rights and procedures are explained on the back of the Notice of Adjustment and should be followed when the sales tax registrant does not agree with the adjustment.

Rejected Returns

The reject notice will contain information about the errors. Rejected returns are not considered filed. The transmission should be corrected and resubmitted. Only an accepted transmission is considered filed and will be issued a confirmation number.

Sales and Use Tax e-File Developer Electronic Mailing lists

If you would like to receive news and reminders from WDOR, subscribe to the WDOR news emailing lists.


Chris Roberts
Mail Stop 4-224
P.O. Box 8933
Madison, WI 53708-8933
E-Mail Additional Questions

March 8, 2012