Periodic Returns. Form MW-506 — quarterly by last day of month following end of quarter if employer withholds less than $700 per quarter; monthly by 15th day of next month if employer withholds $700 or more per quarter (returns for March, June, September, and December are due by last day of following month); annually by January 31 of the following year if less than $250 is withheld.
Annual Reconciliation Returns. Form MW-508 due by February 28.
Timely Filing. When the due date for a return or report falls on
Saturday, Sunday, or a legal holiday, an extension is granted to the first
succeeding working day. A return or report is deemed timely filed if it is
postmarked on the due date or if the return is received by the due date.