Simple plan with 2 partners and multiple employees. All employees defer their SIMPLE contributions through their wage (it is reported in their W-2). When does the partner have until to make his deferral contribution(if he did not make payments during the year)? I know the matching contribution can by made by the due date of the tax return, including extensions. The partner has guaranteed payments and profits on his K-1, but I am not sure when the partner has to make his deferral payment. Is it by Jan 30 of the following year? Anyone know?